diff --git a/crates/cli/src/opts/build/zksync.rs b/crates/cli/src/opts/build/zksync.rs
index d6a0e1c2b..216a37da6 100644
--- a/crates/cli/src/opts/build/zksync.rs
+++ b/crates/cli/src/opts/build/zksync.rs
@@ -1,6 +1,6 @@
 use std::{collections::HashSet, path::PathBuf};
 
-use alloy_primitives::{Address, Bytes};
+use alloy_primitives::{hex, Address, Bytes};
 use clap::Parser;
 use foundry_compilers::zksolc::settings::{ZkSolcError, ZkSolcWarning};
 use foundry_config::ZkSyncConfig;
@@ -115,7 +115,8 @@ pub struct ZkSyncArgs {
     #[clap(
         long = "zk-paymaster-input",
         value_name = "PAYMASTER_INPUT",
-        visible_alias = "paymaster-input"
+        visible_alias = "paymaster-input",
+        value_parser = parse_hex_bytes
     )]
     pub paymaster_input: Option<Bytes>,
 
@@ -185,3 +186,7 @@ impl ZkSyncArgs {
         zksync
     }
 }
+
+fn parse_hex_bytes(s: &str) -> Result<Bytes, String> {
+    hex::decode(s).map(Bytes::from).map_err(|e| format!("Invalid hex string: {e}"))
+}