diff --git a/tests/test_execution_types.nim b/tests/test_execution_types.nim
index 7362490..2e5c074 100644
--- a/tests/test_execution_types.nim
+++ b/tests/test_execution_types.nim
@@ -48,7 +48,7 @@ suite "Execution types tests":
       prevRandao: b32(2),
       suggestedFeeRecipient: address(3),
       withdrawals: Opt.some(@[wd]),
-      parentBeaconBlockRoot: Opt.some(b32(4)),
+      parentBeaconBlockRoot: Opt.some(h256(4)),
     )
 
     blobs = BlobsBundleV1(
@@ -110,7 +110,7 @@ suite "Execution types tests":
 
   test "attr version":
     var v2 = attr
-    v2.parentBeaconBlockRoot = Opt.none(Bytes32)
+    v2.parentBeaconBlockRoot = Opt.none(Hash32)
     var v1 = v2
     v1.withdrawals = Opt.none(seq[WithdrawalV1])
     check attr.version == Version.V3
diff --git a/web3/engine_api.nim b/web3/engine_api.nim
index 09098a7..d5634da 100644
--- a/web3/engine_api.nim
+++ b/web3/engine_api.nim
@@ -26,8 +26,8 @@ createRpcSigsFromNim(RpcClient):
 
   proc engine_newPayloadV1(payload: ExecutionPayloadV1): PayloadStatusV1
   proc engine_newPayloadV2(payload: ExecutionPayloadV2): PayloadStatusV1
-  proc engine_newPayloadV3(payload: ExecutionPayloadV3, expectedBlobVersionedHashes: seq[VersionedHash], parentBeaconBlockRoot: Bytes32): PayloadStatusV1
-  proc engine_newPayloadV4(payload: ExecutionPayloadV4, expectedBlobVersionedHashes: seq[VersionedHash], parentBeaconBlockRoot: Bytes32): PayloadStatusV1
+  proc engine_newPayloadV3(payload: ExecutionPayloadV3, expectedBlobVersionedHashes: seq[VersionedHash], parentBeaconBlockRoot: Hash32): PayloadStatusV1
+  proc engine_newPayloadV4(payload: ExecutionPayloadV4, expectedBlobVersionedHashes: seq[VersionedHash], parentBeaconBlockRoot: Hash32): PayloadStatusV1
   proc engine_forkchoiceUpdatedV1(forkchoiceState: ForkchoiceStateV1, payloadAttributes: Opt[PayloadAttributesV1]): ForkchoiceUpdatedResponse
   proc engine_forkchoiceUpdatedV2(forkchoiceState: ForkchoiceStateV1, payloadAttributes: Opt[PayloadAttributesV2]): ForkchoiceUpdatedResponse
   proc engine_forkchoiceUpdatedV3(forkchoiceState: ForkchoiceStateV1, payloadAttributes: Opt[PayloadAttributesV3]): ForkchoiceUpdatedResponse
@@ -51,10 +51,10 @@ createRpcSigsFromNim(RpcClient):
   proc engine_newPayloadV2(payload: ExecutionPayloadV1OrV2): PayloadStatusV1
   proc engine_newPayloadV3(payload: ExecutionPayload,
     expectedBlobVersionedHashes: Opt[seq[VersionedHash]],
-    parentBeaconBlockRoot: Opt[Bytes32]): PayloadStatusV1
+    parentBeaconBlockRoot: Opt[Hash32]): PayloadStatusV1
   proc engine_newPayloadV4(payload: ExecutionPayload,
     expectedBlobVersionedHashes: Opt[seq[VersionedHash]],
-    parentBeaconBlockRoot: Opt[Bytes32]): PayloadStatusV1
+    parentBeaconBlockRoot: Opt[Hash32]): PayloadStatusV1
   proc engine_forkchoiceUpdatedV2(forkchoiceState: ForkchoiceStateV1, payloadAttributes: Opt[PayloadAttributes]): ForkchoiceUpdatedResponse
   proc engine_forkchoiceUpdatedV3(forkchoiceState: ForkchoiceStateV1, payloadAttributes: Opt[PayloadAttributes]): ForkchoiceUpdatedResponse
 
diff --git a/web3/engine_api_types.nim b/web3/engine_api_types.nim
index 329a79b..c2f3378 100644
--- a/web3/engine_api_types.nim
+++ b/web3/engine_api_types.nim
@@ -200,7 +200,7 @@ type
     prevRandao*: Bytes32
     suggestedFeeRecipient*: Address
     withdrawals*: seq[WithdrawalV1]
-    parentBeaconBlockRoot*: Bytes32
+    parentBeaconBlockRoot*: Hash32
 
   # This is ugly, but see the comment on ExecutionPayloadV1OrV2.
   PayloadAttributesV1OrV2* = object
diff --git a/web3/execution_types.nim b/web3/execution_types.nim
index 83b8652..b40d6f4 100644
--- a/web3/execution_types.nim
+++ b/web3/execution_types.nim
@@ -43,7 +43,7 @@ type
     prevRandao*: Bytes32
     suggestedFeeRecipient*: Address
     withdrawals*: Opt[seq[WithdrawalV1]]
-    parentBeaconBlockRoot*: Opt[Bytes32]
+    parentBeaconBlockRoot*: Opt[Hash32]
 
   SomeOptionalPayloadAttributes* =
     Opt[PayloadAttributesV1] |