diff --git a/autoload/ack.vim b/autoload/ack.vim
index b6afdba4..7b30dd10 100644
--- a/autoload/ack.vim
+++ b/autoload/ack.vim
@@ -15,6 +15,20 @@ endif
 " Public API
 "-----------------------------------------------------------------------------
 
+function! s:FindProjectRoot()
+    let current_dir = expand('%:p:h')
+    while current_dir != '/'
+        for marker in g:ack_root_markers
+            let marker_path = current_dir . '/' . marker
+            if isdirectory(marker_path) || filereadable(marker_path)
+                return current_dir
+            endif
+        endfor
+        let current_dir = fnamemodify(current_dir, ':h')
+    endwhile
+    return ''
+endfunction
+
 function! ack#Ack(cmd, args) "{{{
   call s:Init(a:cmd)
   redraw
@@ -50,13 +64,14 @@ function! ack#Ack(cmd, args) "{{{
   " NOTE: we escape special chars, but not everything using shellescape to
   "       allow for passing arguments etc
   let l:escaped_args = escape(l:grepargs, '|#%')
+  let l:final_args = l:escaped_args.' '.s:FindProjectRoot()
 
   echo "Searching ..."
 
   if g:ack_use_dispatch
-    call s:SearchWithDispatch(l:grepprg, l:escaped_args, l:grepformat)
+    call s:SearchWithDispatch(l:grepprg, l:final_args, l:grepformat)
   else
-    call s:SearchWithGrep(a:cmd, l:grepprg, l:escaped_args, l:grepformat)
+    call s:SearchWithGrep(a:cmd, l:grepprg, l:final_args, l:grepformat)
   endif
 
   " Dispatch has no callback mechanism currently, we just have to display the
diff --git a/doc/ack.txt b/doc/ack.txt
index 22e884bc..14276527 100644
--- a/doc/ack.txt
+++ b/doc/ack.txt
@@ -232,6 +232,19 @@ Example:
 >
         let g:ack_use_cword_for_empty_search = 0
 <
+
+g:ack_root_markers
+Default: ['']
+
+Use this option to enable auto set search directory which contains ack_root_markers, 
+otherwise the search directory will be current directory.
+
+Example:
+>
+        let g:ack_root_markers = ['.git', '.svn', '.hg']
+<
+
+
 ==============================================================================
 MAPPINGS                                                        *ack-mappings*
 
diff --git a/plugin/ack.vim b/plugin/ack.vim
index 202ae2ea..b56c3ba7 100644
--- a/plugin/ack.vim
+++ b/plugin/ack.vim
@@ -67,6 +67,10 @@ if !exists("g:ack_use_cword_for_empty_search")
   let g:ack_use_cword_for_empty_search = 1
 endif
 
+if !exists("g:ack_root_markers")
+  let g:ack_root_markers = ['']
+endif
+
 command! -bang -nargs=* -complete=file Ack           call ack#Ack('grep<bang>', <q-args>)
 command! -bang -nargs=* -complete=file AckAdd        call ack#Ack('grepadd<bang>', <q-args>)
 command! -bang -nargs=* -complete=file AckFromSearch call ack#AckFromSearch('grep<bang>', <q-args>)