diff --git a/src/caosdb/exceptions.py b/src/caosdb/exceptions.py
index 77d094c4f503f28f9bf99c85bfd020f4ed1f442b..2b4a6f18a92e8a336dfcbcf209d73a71246d0dd9 100644
--- a/src/caosdb/exceptions.py
+++ b/src/caosdb/exceptions.py
@@ -347,3 +347,10 @@ class AuthorizationException(EntityError):
     Maybe you need more privileges or a user account at all.
 
     """
+
+
+class AmbiguousEntityError(EntityError):
+    """A retrieve of the entity was not possible because there is more
+    than one possible candidate.
+
+    """