diff --git a/src/event/ngx_event.c b/src/event/ngx_event.c
index c8ae5b2cf9..2f3a098dec 100644
--- a/src/event/ngx_event.c
+++ b/src/event/ngx_event.c
@@ -1261,7 +1261,7 @@ ngx_event_core_init_conf(ngx_cycle_t *cycle, void *conf)
     ngx_conf_init_ptr_value(ecf->name, event_module->name->data);
 
     ngx_conf_init_value(ecf->multi_accept, 0);
-    ngx_conf_init_value(ecf->accept_mutex, 1);
+    ngx_conf_init_value(ecf->accept_mutex, 0);
     ngx_conf_init_msec_value(ecf->accept_mutex_delay, 500);
 
     return NGX_CONF_OK;