diff --git a/src/hub/dataload/sources/chembl/upload.py b/src/hub/dataload/sources/chembl/upload.py
index d2038b2..ee1676e 100644
--- a/src/hub/dataload/sources/chembl/upload.py
+++ b/src/hub/dataload/sources/chembl/upload.py
@@ -9,11 +9,43 @@
 from .parser import load_data
 
 
+class ChemblMergerStorage(storage.MergerStorage):
+    @classmethod
+    def merge_func(klass, doc1, doc2, **kwargs):
+        merged_doc = {"_id": doc1["_id"], "chembl": []}
+        chembl_dict = {}
+
+        for doc in [doc1, doc2]:
+            chembl_list = doc.get("chembl", [])
+            if not isinstance(chembl_list, list):
+                chembl_list = [chembl_list]
+
+            for chembl in chembl_list:
+                uniprot = chembl.get("uniprot")
+                chembl_target = chembl.get("chembl_target")
+
+                if uniprot in chembl_dict:
+                    if isinstance(chembl_dict[uniprot]["chembl_target"], list):
+                        chembl_dict[uniprot]["chembl_target"].append(chembl_target)
+                    else:
+                        chembl_dict[uniprot]["chembl_target"] = [
+                            chembl_dict[uniprot]["chembl_target"],
+                            chembl_target,
+                        ]
+                else:
+                    chembl_dict[uniprot] = {
+                        "chembl_target": chembl_target,
+                        "uniprot": uniprot,
+                    }
+
+        merged_doc["chembl"] = list(chembl_dict.values())
+        return merged_doc
+
+
 class ChemblUploader(uploader.BaseSourceUploader):
     name = "chembl"
 
-    # storage_class = storage.RootKeyMergerStorage
-    storage_class = storage.MergerStorage
+    storage_class = ChemblMergerStorage
     TARGET_FILENAME_PATTERN = "target.*.json"
 
     keylookup = MyGeneKeyLookup(