diff --git a/src/index/txindex.h b/src/index/txindex.h
--- a/src/index/txindex.h
+++ b/src/index/txindex.h
@@ -46,7 +46,7 @@
     /// in.
     /// @param[out]  tx  The transaction itself.
     /// @return  true if transaction is found, false otherwise
-    bool FindTx(const TxId &txid, uint256 &block_hash,
+    bool FindTx(const TxId &txid, BlockHash &block_hash,
                 CTransactionRef &tx) const;
 };
 
diff --git a/src/index/txindex.cpp b/src/index/txindex.cpp
--- a/src/index/txindex.cpp
+++ b/src/index/txindex.cpp
@@ -266,7 +266,7 @@
     return *m_db;
 }
 
-bool TxIndex::FindTx(const TxId &txid, uint256 &block_hash,
+bool TxIndex::FindTx(const TxId &txid, BlockHash &block_hash,
                      CTransactionRef &tx) const {
     CDiskTxPos postx;
     if (!m_db->ReadTxPos(txid, postx)) {
diff --git a/src/test/txindex_tests.cpp b/src/test/txindex_tests.cpp
--- a/src/test/txindex_tests.cpp
+++ b/src/test/txindex_tests.cpp
@@ -20,7 +20,7 @@
     TxIndex txindex(1 << 20, true);
 
     CTransactionRef tx_disk;
-    uint256 block_hash;
+    BlockHash block_hash;
 
     // Transaction should not be found in the index before it is started.
     for (const auto &txn : m_coinbase_txns) {