diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index 470a0e7..54fdadf 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -7,6 +7,7 @@ on:
       - cron: '00 4 * * *'  # daily at 4AM
 
 jobs:
+
   build:
 
     runs-on: ubuntu-latest
diff --git a/pyscicat/client.py b/pyscicat/client.py
index 3056850..d90aea4 100644
--- a/pyscicat/client.py
+++ b/pyscicat/client.py
@@ -273,6 +273,75 @@ def upload_derived_dataset(self, dataset: Dataset) -> str:
         logger.info(f"new dataset created {new_pid}")
         return new_pid
 
+    def upsert_raw_dataset(self, dataset: Dataset, filter_fields) -> str:
+        """Upsert a raw dataset
+
+        Parameters
+        ----------
+        dataset : Dataset
+            Dataset to load
+
+        filter_fields
+            Filters to locate where to upsert dataset
+
+        Returns
+        -------
+        str
+            pid (or unique identifier) of the dataset
+
+        Raises
+        ------
+        ScicatCommError
+            Raises if a non-20x message is returned
+        """
+        query_results = self.get_datasets(filter_fields)
+        if not query_results:
+            logger.info("Dataset does not exist already, will be inserted")
+        filter_fields = json.dumps(filter_fields)
+        raw_dataset_url = f'{self._base_url}/RawDatasets/upsertWithWhere?where={{"where":{filter_fields}}}'
+        resp = self._send_to_scicat(raw_dataset_url, dataset.dict(exclude_none=True))
+        if not resp.ok:
+            err = resp.json()["error"]
+            raise ScicatCommError(f"Error upserting raw dataset {err}")
+        new_pid = resp.json().get("pid")
+        logger.info(f"dataset upserted {new_pid}")
+        return new_pid
+
+    def upsert_derived_dataset(self, dataset: Dataset, filter_fields) -> str:
+        """Upsert a derived dataset
+
+        Parameters
+        ----------
+        dataset : Dataset
+            Dataset to upsert
+
+        filter_fields
+            Filters to locate where to upsert dataset
+
+        Returns
+        -------
+        str
+            pid (or unique identifier) of the dataset
+
+        Raises
+        ------
+        ScicatCommError
+            Raises if a non-20x message is returned
+        """
+
+        query_results = self.get_datasets(filter_fields)
+        if not query_results:
+            logger.info("Dataset does not exist already, will be inserted")
+        filter_fields = json.dumps(filter_fields)
+        dataset_url = f'{self._base_url}/DerivedDatasets/upsertWithWhere?where={{"where":{filter_fields}}}'
+        resp = self._send_to_scicat(dataset_url, dataset.dict(exclude_none=True))
+        if not resp.ok:
+            err = resp.json()["error"]
+            raise ScicatCommError(f"Error upserting derived dataset {err}")
+        new_pid = resp.json().get("pid")
+        logger.info(f"dataset upserted {new_pid}")
+        return new_pid
+
     def upload_datablock(self, datablock: Datablock, datasetType: str = "RawDatasets"):
         """Upload a Datablock
 
diff --git a/pyscicat/tests/test_client.py b/pyscicat/tests/test_client.py
index 39ba2ca..b9201d1 100644
--- a/pyscicat/tests/test_client.py
+++ b/pyscicat/tests/test_client.py
@@ -15,6 +15,7 @@
     Datablock,
     DataFile,
     Dataset,
+    RawDataset,
     Ownable,
 )
 
@@ -28,6 +29,26 @@ def add_mock_requests(mock_request):
     )
     mock_request.post(local_url + "Samples", json={"sampleId": "dataset_id"})
     mock_request.post(local_url + "RawDatasets/replaceOrCreate", json={"pid": "42"})
+    mock_request.get(
+        local_url
+        + "/Datasets/?filter=%7B%22where%22:%7B%22sampleId%22:%20%22gargleblaster%22%7D%7D",
+        json={"response": "random"},
+    )
+    mock_request.get(
+        local_url
+        + "/Datasets/?filter=%7B%22where%22:%7B%22sampleId%22:%20%22wowza%22%7D%7D",
+        json={"response": "random"},
+    )
+    mock_request.post(
+        local_url
+        + "/RawDatasets/upsertWithWhere?where=%7B%22where%22:%7B%22sampleId%22:%20%22gargleblaster%22%7D%7D",
+        json={"pid": "42"},
+    )
+    mock_request.post(
+        local_url
+        + "/RawDatasets/upsertWithWhere?where=%7B%22where%22:%7B%22sampleId%22:%20%22wowza%22%7D%7D",
+        json={"pid": "54"},
+    )
     mock_request.post(
         local_url + "RawDatasets/42/origdatablocks",
         json={"response": "random"},
@@ -80,6 +101,33 @@ def test_scicate_ingest():
         )
         dataset_id = scicat.upload_raw_dataset(dataset)
 
+        # new dataset
+        dataset = RawDataset(
+            path="/foo/bar",
+            size=42,
+            owner="slartibartfast",
+            contactEmail="slartibartfast@magrathea.org",
+            creationLocation="magrathea",
+            creationTime=str(datetime.now()),
+            type="raw",
+            instrumentId="earth",
+            proposalId="deepthought",
+            dataFormat="planet",
+            principalInvestigator="A. Mouse",
+            sourceFolder="/foo/bar",
+            scientificMetadata={"a": "newfield"},
+            sampleId="gargleblaster",
+            **ownable.dict()
+        )
+
+        # Update existing record
+        dataset_id = scicat.upsert_raw_dataset(dataset, {"sampleId": "gargleblaster"})
+        assert dataset_id == "42"
+
+        # Upsert non-existing record
+        dataset_id_2 = scicat.upsert_raw_dataset(dataset, {"sampleId": "wowza"})
+        assert dataset_id_2 == "54"
+
         # Datablock with DataFiles
         data_file = DataFile(path="/foo/bar", size=42)
         data_block = Datablock(
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 42d5247..7c4c01d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -7,7 +7,6 @@ pytest
 sphinx
 twine
 black
-nbstripout
 requests_mock
 # These are dependencies of various sphinx extensions for documentation.
 ipython