diff --git a/CHANGELOG.md b/CHANGELOG.md
index a86bd3af..8f5da849 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 ### Changed
 
 - **aiken**: `check` now also runs and reports on any `test` found in the project
+- **aiken**: fix Plutus V1 `to_plutus_data()` for post-alonzo txout with no datum hash
 
 ### Removed
 
diff --git a/crates/uplc/src/tx/to_plutus_data.rs b/crates/uplc/src/tx/to_plutus_data.rs
index e8aea41d..3ed82396 100644
--- a/crates/uplc/src/tx/to_plutus_data.rs
+++ b/crates/uplc/src/tx/to_plutus_data.rs
@@ -296,7 +296,7 @@ impl ToPlutusData for TxOut {
                         post_alonzo_output.value.to_plutus_data(),
                         match post_alonzo_output.datum_option {
                             Some(DatumOption::Hash(hash)) => Some(hash).to_plutus_data(),
-                            _ => None::<DatumOption>.to_plutus_data(),
+                            _ => None::<Option<Hash<32>>>.to_plutus_data(),
                         },
                     ],
                 ),