diff --git a/test/core/network_benchmarks/low_level_ping_pong.c b/test/core/network_benchmarks/low_level_ping_pong.c
index 1b40895a7194028cbb6360d3092c16d449085acf..9038d076755fa74c05eecff92267b48d5062ac59 100644
--- a/test/core/network_benchmarks/low_level_ping_pong.c
+++ b/test/core/network_benchmarks/low_level_ping_pong.c
@@ -583,7 +583,7 @@ static int run_benchmark(char *socket_type, thread_args *client_args,
     return rv;
   }
 
-  gpr_log(GPR_INFO, "Starting test %s %s %d", client_args->strategy_name,
+  gpr_log(GPR_INFO, "Starting test %s %s %zu", client_args->strategy_name,
           socket_type, client_args->msg_size);
 
   gpr_thd_new(&tid, server_thread_wrap, server_args, NULL);