diff --git a/avro.cabal b/avro.cabal
--- a/avro.cabal
+++ b/avro.cabal
@@ -1,7 +1,7 @@
 cabal-version:  2.2
 
 name:           avro
-version:        0.4.5.3
+version:        0.4.5.4
 synopsis:       Avro serialization support for Haskell
 description:    Avro serialization and deserialization support for Haskell
 category:       Data
diff --git a/src/Data/Avro/Schema.hs b/src/Data/Avro/Schema.hs
--- a/src/Data/Avro/Schema.hs
+++ b/src/Data/Avro/Schema.hs
@@ -767,6 +767,10 @@
         modify' (HashMap.insert name r')
         pure r'
 
+      r@Enum{name} -> do
+        modify' (HashMap.insert name r)
+        pure r
+
       other -> pure other
 
 -- | Merge two schemas to produce a third.