diff --git a/cgsmiles/pysmiles_utils.py b/cgsmiles/pysmiles_utils.py
index 83051bd..419efb3 100644
--- a/cgsmiles/pysmiles_utils.py
+++ b/cgsmiles/pysmiles_utils.py
@@ -83,6 +83,11 @@ def rebuild_h_atoms(mol_graph, keep_bonding=False):
             ref_node = next(mol_graph.neighbors(node))
             mol_graph.nodes[node]["fragid"] = mol_graph.nodes[ref_node]["fragid"]
             mol_graph.nodes[node]["fragname"] = mol_graph.nodes[ref_node]["fragname"]
+        if mol_graph.nodes[node].get("element", "*") == "H":
+            # make sure the weights are copied for implicit h-atoms
+            anchor = list(mol_graph.neighbors(node))[0]
+            weight = mol_graph.nodes[anchor].get("weight", 1)
+            mol_graph.nodes[node]["weight"] = weight
 
 def annotate_ez_isomers(molecule):
     """
diff --git a/cgsmiles/read_fragments.py b/cgsmiles/read_fragments.py
index f065317..fa28829 100644
--- a/cgsmiles/read_fragments.py
+++ b/cgsmiles/read_fragments.py
@@ -95,6 +95,31 @@ def collect_ring_number(smile_iter, token, node_count, rings):
 
     return smile_iter, token, partial_str, rings
 
+def get_weight(smile_iter):
+    """
+    Extracts weights given to atoms/nodes in
+    fragments. The iter should be advanced
+    up to the weight marker ;.
+
+    Parameters
+    ----------
+    smile_iter: class.PeekIter
+
+    Returns
+    -------
+    float:
+        the weight
+    PeekIter
+        the advanced iter object
+    """
+    num = []
+    for digit in smile_iter:
+        num.append(digit)
+        if smile_iter.peek() in [']', '@', 'H']:
+            break
+    out = float("".join(num))
+    return out, smile_iter
+
 def strip_bonding_descriptors(fragment_string):
     """
     Processes a CGSmiles fragment string by
@@ -122,6 +147,7 @@ def strip_bonding_descriptors(fragment_string):
     rings = defaultdict(list)
     ez_isomer_atoms = {}
     rs_isomers = {}
+    weights = {}
     smile = ""
     node_count = 0
     prev_node = 0
@@ -147,6 +173,8 @@ def strip_bonding_descriptors(fragment_string):
                 bonding_descrpt[prev_node].append(bond_descrp + str(order))
             else:
                 atom = token
+                # set the default weight
+                weights[node_count] = 1
                 while peek != ']':
                     # deal with rs chirality
                     if peek == '@':
@@ -154,6 +182,10 @@ def strip_bonding_descriptors(fragment_string):
                         if smile_iter.peek() == '@':
                             chiral_token = '@' + next(smile_iter)
                         rs_isomers[node_count] = (chiral_token, [])
+                    # we have weights
+                    elif peek == ';':
+                        weight, smile_iter = get_weight(smile_iter)
+                        weights[node_count] = weight
                     else:
                         atom += peek
                     peek = next(smile_iter)
@@ -193,6 +225,8 @@ def strip_bonding_descriptors(fragment_string):
                 smile += token
             current_order = None
             prev_node = node_count
+            # set default weight
+            weights[node_count] = 1
             node_count += 1
 
     # we need to annotate rings to the chiral isomers
@@ -201,7 +235,8 @@ def strip_bonding_descriptors(fragment_string):
             if node in ring_nodes:
                 bonded_node = _find_bonded_ring_node(ring_nodes, node)
                 rs_isomers[node][1].append(bonded_node)
-    return smile, bonding_descrpt, rs_isomers, ez_isomer_atoms
+
+    return smile, bonding_descrpt, rs_isomers, ez_isomer_atoms, weights
 
 def fragment_iter(fragment_str, all_atom=True):
     """
@@ -230,8 +265,8 @@ def fragment_iter(fragment_str, all_atom=True):
     for fragment in fragment_str[1:-1].split(','):
         delim = fragment.find('=', 0)
         fragname = fragment[1:delim]
-        big_smile = fragment[delim+1:]
-        smile, bonding_descrpt, rs_isomers, ez_isomers = strip_bonding_descriptors(big_smile)
+        frag_smile = fragment[delim+1:]
+        smile, bonding_descrpt, rs_isomers, ez_isomers, weights = strip_bonding_descriptors(frag_smile)
         if smile == "H":
             mol_graph = nx.Graph()
             mol_graph.add_node(0, element="H", bonding=bonding_descrpt[0])
@@ -258,6 +293,7 @@ def fragment_iter(fragment_str, all_atom=True):
 
         nx.set_node_attributes(mol_graph, fragname, 'fragname')
         nx.set_node_attributes(mol_graph, 0, 'fragid')
+        nx.set_node_attributes(mol_graph, weights, 'weight')
         yield fragname, mol_graph
 
 def read_fragments(fragment_str, all_atom=True, fragment_dict=None):
diff --git a/cgsmiles/tests/test_molecule_resolve.py b/cgsmiles/tests/test_molecule_resolve.py
index afdbf89..14b1d70 100644
--- a/cgsmiles/tests/test_molecule_resolve.py
+++ b/cgsmiles/tests/test_molecule_resolve.py
@@ -40,7 +40,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
     assert new_btypes == btypes
 
 
-@pytest.mark.parametrize('smile, ref_frags, elements, ref_edges, chiral, ez',(
+@pytest.mark.parametrize('smile, ref_frags, elements, ref_edges, chiral, ez, weights',(
                         # smiple linear seqeunce
                         ("{[#OHter][#PEO]|2[#OHter]}.{#PEO=[$]COC[$],#OHter=[$][O]}",
                         #           0 1             2 3 4 5 6 7 8
@@ -51,7 +51,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [(0, 1), (0, 2), (2, 3), (3, 4), (2, 5), (2, 6), (4, 7),
                          (4, 8), (4, 9), (9, 10), (10, 11), (9, 12), (9, 13),
                          (11, 14), (11, 15), (11, 16), (16, 17)],
-                        {}, {}),
+                        {}, {}, {}),
                         # smiple linear seqeunce with bond-order in link
                         ("{[#TC1][#TC4][#TC1]}.{#TC1=[$1]=CC=[$2],#TC4=[$1]=CC=[$2]}",
                         #         0 1 2 3 4 5            6 7 8 9
@@ -61,7 +61,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'C C H H H H C C H H C C H H H H',
                         [(0, 1), (0, 2), (1, 3), (1, 4), (1, 5), (0, 6), (6, 7),
                          (6, 8), (7, 9), (7, 11), (10, 11), (10, 12), (10, 13),
-                         (10, 14), (11, 15)], {}, {}),
+                         (10, 14), (11, 15)], {}, {}, {}),
                         # smiple linear seqeunce unconsumed bonding descrpt
                         ("{[#OHter][#PEO]|2[#OHter]}.{#PEO=[$]CO[>]C[$],#OHter=[$][O]}",
                         #           0 1             2 3 4 5 6 7 8
@@ -71,7 +71,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'O H C O C H H H H C O C H H H H O H',
                         [(0, 1), (0, 2), (2, 3), (3, 4), (2, 5), (2, 6), (4, 7),
                          (4, 8), (4, 9), (9, 10), (10, 11), (9, 12), (9, 13),
-                         (11, 14), (11, 15), (11, 16), (16, 17)], {}, {}),
+                         (11, 14), (11, 15), (11, 16), (16, 17)], {}, {}, {}),
                         # smiple linear seqeunce with ionic bond
                         ("{[#OHter][#PEO]|2[#OHter]}.{#PEO=[$]COC[$],#OHter=[$][O-].[Na+]}",
                         #           0 1             2 3 4 5 6 7 8
@@ -81,7 +81,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'O Na C O C H H H H C O C H H H H O Na',
                         [(0, 1), (0, 2), (2, 3), (3, 4), (2, 5), (2, 6), (4, 7),
                          (4, 8), (4, 9), (9, 10), (10, 11), (9, 12), (9, 13),
-                         (11, 14), (11, 15), (11, 16), (16, 17)], {}, {}),
+                         (11, 14), (11, 15), (11, 16), (16, 17)], {}, {}, {}),
                         # smiple linear seqeunce with ionic ending
                         ("{[#OH][#PEO]|2[#ON]}.{#PEO=[$]COC[$],#OH=[$]O,#ON=[$][O-]}",
                         #           0 1             2 3 4 5 6 7 8
@@ -91,7 +91,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'O H C O C H H H H C O C H H H H O',
                         [(0, 1), (0, 2), (2, 3), (3, 4), (2, 5), (2, 6), (4, 7),
                          (4, 8), (4, 9), (9, 10), (10, 11), (9, 12), (9, 13),
-                         (11, 14), (11, 15), (11, 16)], {}, {}),
+                         (11, 14), (11, 15), (11, 16)], {}, {}, {}),
                         # uncomsumed bonding IDs; note that this is not the same
                         # molecule as previous test case. Here one of the OH branches
                         # and replaces an CH2 group with CH-OH
@@ -103,7 +103,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'O H C O C H H H H C O C H H H H O H',
                         [(0, 1), (0, 2), (2, 3), (2, 5), (2, 11), (3, 4),
                          (4, 6), (4, 7), (4, 8), (9, 10), (9, 12), (9, 13),
-                         (10, 11), (11, 15), (11, 14), (9, 16), (16, 17)], {}, {}),
+                         (10, 11), (11, 15), (11, 14), (9, 16), (16, 17)], {}, {}, {}),
                         # simple branched sequence
                         ("{[#Hter][#PE]([#PEO][#Hter])[#PE]([#PEO][#Hter])[#Hter]}.{#Hter=[$]H,#PE=[$]CC[$][$],#PEO=[$]COC[$]}",
                         [('Hter', 'H'), ('PE', 'C C H H H'), ('PEO', 'C O C H H H H'), ('Hter', 'H'),
@@ -111,7 +111,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'H C C H H H C O C H H H H H C C H H H C O C H H H H H H',
                         [(0, 1), (1, 2), (1, 3), (1, 4), (2, 5), (2, 6), (2, 14), (6, 7), (6, 9), (6, 10), (7, 8),
                          (8, 11), (8, 12), (8, 13), (14, 15), (14, 16), (14, 17), (15, 18), (15, 19), (15, 27),
-                         (19, 20), (19, 22), (19, 23), (20, 21), (21, 24), (21, 25), (21, 26)], {}, {}),
+                         (19, 20), (19, 22), (19, 23), (20, 21), (21, 24), (21, 25), (21, 26)], {}, {}, {}),
                         # something with a ring
                         #            012 34567
                         #            890123456
@@ -124,7 +124,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                          (6, 14), (7, 8), (7, 15), (8, 16), (17, 18), (17, 25),
                          (17, 26), (18, 19), (18, 27), (18, 33), (19, 20), (19, 24),
                          (20, 21), (20, 28), (21, 22), (21, 29), (22, 23), (22, 30),
-                         (23, 24), (23, 31), (24, 32)], {}, {}),
+                         (23, 24), (23, 31), (24, 32)], {}, {}, {}),
                         # something more complicated branched
                         # here we have multiple bonding descriptors
 #                       # despite being the same residue we have 3 fragments after adding hydrgens
@@ -146,7 +146,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [('A', 'O H C H H'), ('B', 'C H H C H H H'),],
                         'O H C H H C H H H',
                         [(0, 1), (0, 2), (2, 3), (2, 4), (2, 5),
-                         (5, 6), (5, 7), (5, 8)], {}, {}),
+                         (5, 6), (5, 7), (5, 8)], {}, {}, {}),
                         # smiple squash operator; unconsumed operators
                         ("{[#A][#B]}.{#A=OC[!],#B=[$][!]CC}",
                         #       0 1 2 3 4           1 5 3 4 6 7 8
@@ -157,7 +157,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [('A', 'O H C H H'), ('B', 'C H H C H H H'),],
                         'O H C H H C H H H',
                         [(0, 1), (0, 2), (2, 3), (2, 4), (2, 5),
-                         (5, 6), (5, 7), (5, 8)], {}, {}),
+                         (5, 6), (5, 7), (5, 8)], {}, {}, {}),
                         # smiple squash operator; plus connect operator
                         ("{[#A][#B][#C]}.{#A=OC[!],#B=[$][!]CC,#C=[$]O}",
                         #       0 1 2 3 4           1 5 3 4 6 7 8
@@ -168,7 +168,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [('A', 'O H C H'), ('B', 'C H C H H H'), ('C', 'O H')],
                         'O H C H C H H H O H',
                         [(0, 1), (0, 2), (2, 3), (2, 4),
-                         (4, 5), (4, 6), (4, 7), (2, 8), (8, 9)], {}, {}),
+                         (4, 5), (4, 6), (4, 7), (2, 8), (8, 9)], {}, {}, {}),
                         # THF like test case with double edge and squash operator
                         ("{[#A]=[#B]}.{#A=[!]COC[!],#B=[!]CCCC[!]}",
                         [('A', 'O C C H H H H'),
@@ -176,7 +176,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'O C C H H H H C C H H H H',
                         [(0, 2), (0, 3), (2, 4), (2, 5),
                          (3, 6), (3, 7), (2, 8), (3, 9),
-                         (8, 9), (9, 12), (9, 13), (8, 10), (8, 11)], {}, {}),
+                         (8, 9), (9, 12), (9, 13), (8, 10), (8, 11)], {}, {}, {}),
                         # Toluene like test case with squash operator and aromaticity
                         ("{[#SC3]1[#TC5][#TC5]1}.{#SC3=Cc(c[!])c[!],#TC5=[!]ccc[!]}",
                         [('SC3', 'C C H H H C H C H'),
@@ -184,7 +184,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         'C C H H H C H C H C H C H C H',
                         [(0, 1), (0, 2), (0, 3), (0, 4), (1, 5),
                          (1, 7), (5, 9), (5, 6), (7, 13), (7, 8),
-                         (9, 11), (9, 10), (11, 13), (11, 12), (13, 14)], {}, {}),
+                         (9, 11), (9, 10), (11, 13), (11, 12), (13, 14)], {}, {}, {}),
                          # simple chirality assigment with rings
                          ("{[#GLC]}.{#GLC=C([C@@H]1[C@H]([C@@H]([C@H]([C@H](O1)O)O)O)O)O}",
                          # 0 1 2 3
@@ -194,7 +194,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                           (2, 15), (3, 4), (3, 9), (3, 16), (4, 5), (4, 8), (4, 17), (5, 6), (5, 7), (5, 18),
                           (7, 19), (8, 20), (9, 21), (10, 22), (11, 23)],
                          {1: (6, 14, 2, 0), 2: (1, 15, 3, 10), 3: (2, 16, 9, 4),
-                          4: (3, 17, 5, 8), 5: (4, 18, 6, 7)}, {}),
+                          4: (3, 17, 5, 8), 5: (4, 18, 6, 7)}, {}, {}),
                         # simple chirality assigment between fragments
                         ("{[#A][#B][#C]}.{#A=O[>],#C=O[<],#B=[<]C[C@H][>]C(=O)OC}",
                         # 0 1 2 3
@@ -204,7 +204,7 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [(0, 1), (0, 2), (2, 3), (2, 4),
                          (2, 5), (5, 6), (5, 7), (7, 8), (7, 9), (9, 10), (10, 11), (10, 12),
                          (10, 13), (5, 14), (14, 15)],
-                        {3: (2, 10, 4, 14)}, {}),
+                        {3: (2, 10, 4, 14)}, {}, {}),
                         # simple chirality assigment between fragments inv
                         ("{[#A][#B][#C]}.{#A=O[>],#C=O[<],#B=[<]C[C@@H][>]C(=O)OC}",
                         # 0 1 2 3
@@ -214,21 +214,21 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                         [(0, 1), (0, 2), (2, 3), (2, 4),
                          (2, 5), (5, 6), (5, 7), (7, 8), (7, 9), (9, 10), (10, 11), (10, 12),
                          (10, 13), (5, 14), (14, 15)],
-                        {3: (2, 10, 14, 4)}, {}),
+                        {3: (2, 10, 14, 4)}, {}, {}),
                         # smiple ez isomerism assigment between fragments inv
                         ("{[#A][#B]}.{#A=CC(/F)=[$],#B=[$]=C(\F)C}",
                         [('A', 'C C F H H H'), ('B', 'C F C H H H')],
                         'C C F H H H F C C H H H',
                         [(0, 1), (1, 2), (0, 3), (0, 4),
                          (0, 5), (1, 7), (7, 6), (7, 8), (8, 9), (8, 10), (8, 11)],
-                        {}, {2: (2, 1, 6, 7, 'trans'), 7: (7, 6, 1, 2, 'trans')}),
+                        {}, {2: (2, 1, 6, 7, 'trans'), 7: (7, 6, 1, 2, 'trans')}, {}),
                         # simple ez isomerism assigment between fragments inv
                         ("{[#A][#B]}.{#A=CC(/F)=[$],#B=[$]=C(/F)C}",
                         [('A', 'C C F H H H'), ('B', 'C F C H H H')],
                         'C C F H H H F C C H H H',
                         [(0, 1), (1, 2), (0, 3), (0, 4),
                          (0, 5), (1, 7), (7, 6), (7, 8), (8, 9), (8, 10), (8, 11)],
-                        {}, {2: (2, 1, 6, 7, 'cis'), 7: (7, 6, 1, 2, 'cis')}),
+                        {}, {2: (2, 1, 6, 7, 'cis'), 7: (7, 6, 1, 2, 'cis')}, {}),
                         # test skip virtual nodes
                         ("{[#SP4]1.2[#SP4].3[#SP1r]1.[#TC4]23}.{#SP4=OC[$]C[$]O,#SP1r=[$]OC[$]CO}",
                         [('SP4', 'O C C O H H H H'), ('SP4', 'O C C O H H H H'),
@@ -238,9 +238,29 @@ def test_match_bonding_descriptors(bonds_source, bonds_target, edge, btypes):
                          (3, 7), (8, 9), (8, 12), (9, 10), (9, 13), (10, 11), (10, 17),
                          (10, 14), (11, 15), (16, 17), (17, 18), (17, 20), (18, 19),
                          (18, 21), (18, 22), (19, 23)],
-                        {},{}),
+                        {},{}, {}),
+                        # test weights
+                        ("{[#SP4]1[#SP4][#SP1r]1}.{#SP4=[OH;0.5]C[$]C[$]O,#SP1r=[$]OC[$]CO}",
+                        [('SP4', 'O C C O H H H H'), ('SP4', 'O C C O H H H H'),
+                         ('SP1r', 'O C C O H H H H')],
+                        'O C C O H H H H O C C O H H H H O C C O H H H H',
+                        [(0, 1), (0, 4), (1, 2), (1, 9), (1, 5), (2, 3), (2, 16), (2, 6),
+                         (3, 7), (8, 9), (8, 12), (9, 10), (9, 13), (10, 11), (10, 17),
+                         (10, 14), (11, 15), (16, 17), (17, 18), (17, 20), (18, 19),
+                         (18, 21), (18, 22), (19, 23)],
+                        {},{}, {0: 0.5, 4: 0.5, 8: 0.5, 12: 0.5}),
+                        # test 2 weights
+                        ("{[#SP4]1[#SP4][#SP1r]1}.{#SP4=[OH;0.5][C;0.1][$]C[$]O,#SP1r=[$]OC[$]CO}",
+                        [('SP4', 'O C C O H H H H'), ('SP4', 'O C C O H H H H'),
+                         ('SP1r', 'O C C O H H H H')],
+                        'O C C O H H H H O C C O H H H H O C C O H H H H',
+                        [(0, 1), (0, 4), (1, 2), (1, 9), (1, 5), (2, 3), (2, 16), (2, 6),
+                         (3, 7), (8, 9), (8, 12), (9, 10), (9, 13), (10, 11), (10, 17),
+                         (10, 14), (11, 15), (16, 17), (17, 18), (17, 20), (18, 19),
+                         (18, 21), (18, 22), (19, 23)],
+                        {},{}, {0: 0.5, 1: 0.1, 5: 0.1, 4: 0.5, 8: 0.5, 9: 0.1, 12: 0.5, 13: 0.1}),
 ))
-def test_all_atom_resolve_molecule(smile, ref_frags, elements, ref_edges, chiral, ez):
+def test_all_atom_resolve_molecule(smile, ref_frags, elements, ref_edges, chiral, ez, weights):
     meta_mol, molecule = MoleculeResolver.from_string(smile).resolve()
 
     # loop and compare fragments first
@@ -278,6 +298,12 @@ def _ele_match(n1, n2):
     if ez:
         ez_assigned = nx.get_node_attributes(molecule, 'ez_isomer')
         assert ez == ez_assigned
+    # check weights
+    if weights:
+        mol_weights = {node: 1 for node in ref_graph}
+        mol_weights.update(weights)
+        weights_assigned = nx.get_node_attributes(molecule, 'weight')
+        assert mol_weights == weights_assigned
 
 @pytest.mark.parametrize('case, cgsmiles_str, ref_string',(
     # case 1: here only the meta-graph is described by the