diff --git a/scouter/activities/mongodb.py b/scouter/activities/mongodb.py
index 485a492..87fbc51 100644
--- a/scouter/activities/mongodb.py
+++ b/scouter/activities/mongodb.py
@@ -92,11 +92,14 @@ class MongoDB(BaseActivity):
 
         try:
 
-            data_filter = {
-                "inserted_at": {
-                    "$gt": datetime.strptime(last_data_timestamp, "%Y-%m-%d %H:%M:%S.%f")
+            if last_data_timestamp is None:
+                data_filter = {}
+            else:
+                data_filter = {
+                    "inserted_at": {
+                        "$gt": datetime.strptime(last_data_timestamp, "%Y-%m-%d %H:%M:%S.%f")
+                    }
                 }
-            }
 
             data = self.database[collection_name].find(data_filter, {"_id": 0})