I know about os.nice() it works perfect for parent process, but I need to do renice of my child subprocesses. I found way to do this, but it seems to be not very handy and too excessive: os.system("renice -n %d %d" % ( new_nice, suprocess.pid ) ) And it isn't return resulting nice level after renicing. Is there more clean way to renice subprocesses in python?