diff --git a/src/os/unix/ngx_process_cycle.c b/src/os/unix/ngx_process_cycle.c
index 9d23a73d0..499039a7e 100644
--- a/src/os/unix/ngx_process_cycle.c
+++ b/src/os/unix/ngx_process_cycle.c
@@ -959,6 +959,8 @@ ngx_worker_process_init(ngx_cycle_t *cycle, ngx_int_t worker)
                       "sigprocmask() failed");
     }
 
+    srandom((ngx_pid << 16) ^ ngx_time());
+
     /*
      * disable deleting previous events for the listening sockets because
      * in the worker processes there are no events at all at this point
diff --git a/src/os/win32/ngx_win32_init.c b/src/os/win32/ngx_win32_init.c
index d2505ced4..d3cc37603 100644
--- a/src/os/win32/ngx_win32_init.c
+++ b/src/os/win32/ngx_win32_init.c
@@ -228,7 +228,7 @@ ngx_os_init(ngx_log_t *log)
         ngx_sprintf((u_char *) ngx_unique, "%P%Z", ngx_pid);
     }
 
-    srand((unsigned) ngx_time());
+    srand((ngx_pid << 16) ^ (unsigned) ngx_time());
 
     return NGX_OK;
 }