diff --git a/beacon_node/execution_layer/src/engine_api/json_structures.rs b/beacon_node/execution_layer/src/engine_api/json_structures.rs
index 99459ec2b..4f372beda 100644
--- a/beacon_node/execution_layer/src/engine_api/json_structures.rs
+++ b/beacon_node/execution_layer/src/engine_api/json_structures.rs
@@ -345,6 +345,7 @@ impl<T: EthSpec> TryFrom<ExecutionPayload<T>> for JsonExecutionPayloadV2<T> {
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
 pub struct JsonWithdrawal {
     #[serde(with = "eth2_serde_utils::u64_hex_be")]
     pub index: u64,