diff --git a/benches/benchmarks/external_process.rs b/benches/benchmarks/external_process.rs
index 3ec6092..08297b0 100644
--- a/benches/benchmarks/external_process.rs
+++ b/benches/benchmarks/external_process.rs
@@ -22,11 +22,12 @@ fn python_fibonacci(c: &mut Criterion) {
         .is_ok();
 
     if has_python3 {
-        let process = create_command()
+        let mut process = create_command()
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
             .spawn()
             .expect("Unable to start python process");
+        process.wait().expect("failed to wait on child");
 
         let mut stdin = process.stdin.expect("Unable to get stdin for child process");
         let stdout = process.stdout.expect("Unable to get stdout for child process");