diff --git a/hotdog/command/ddf.py b/hotdog/command/ddf.py
index 7c77b97..622389d 100644
--- a/hotdog/command/ddf.py
+++ b/hotdog/command/ddf.py
@@ -25,7 +25,7 @@ def load_db(fp):
     for ep in Episode.from_csv(fp):
         if ep.nr_europa:
             db[ep.nr_europa.lower()] = ep
-        elif ep.nr_kosmos:
+        elif ep.nr_kosmos and ep.nr_kosmos.lower() not in db:
             db[ep.nr_kosmos.lower()] = ep
         if ep.title_de:
             db[ep.title_de.lower()] = ep