--- a/src/os/unix/ngx_process_cycle.c
+++ b/src/os/unix/ngx_process_cycle.c
@@ -853,7 +853,7 @@
     }
 #endif
 
-    if (geteuid() == 0) {
+    if (ccf->user != 0 && geteuid() == 0) {
         if (setgid(ccf->group) == -1) {
             ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                           "setgid(%d) failed", ccf->group);