diff --git a/src/api/step_launch.c b/src/api/step_launch.c
index 8743c872038dfd07b31cd16e2875a81e54d353e5..332dc4c380c7e1973d025cd89392c0c095579f06 100644
--- a/src/api/step_launch.c
+++ b/src/api/step_launch.c
@@ -134,6 +134,8 @@ int slurm_step_launch (slurm_step_ctx ctx,
 	char **env = NULL;
 
 	debug("Entering slurm_step_launch");
+	memset(&launch, 0, sizeof(launch));
+
 	if (ctx == NULL || ctx->magic != STEP_CTX_MAGIC) {
 		error("Not a valid slurm_step_ctx!");