diff --git a/dsmz-match.py b/dsmz-match.py
index c0bdee1e289612d4e4cb29860ae74f5b49cb92df..685aea9c08897294925c534b7c32c0b90441506b 100755
--- a/dsmz-match.py
+++ b/dsmz-match.py
@@ -92,6 +92,8 @@ class BacDiveEntry:
         return None
 
     def _dispatch(self, ncbi_taxa):
+        if len(self.strain_number) == 0:
+            return 'no-number', None
         for n in itertools.chain(self.strain_number, self.complete_name):
             taxid = self._match(ncbi_taxa, n, 'no rank')
             if taxid is not None: