The men, one of whom had a gun, entered the Peking House restaurant in Springfield at about 8 p.m. Monday.
A female employee saw the gun, ran out the back and called police.
Police say the thieves couldn't figure out how to open the cash drawer, so they took off.
Police scoured the neighborhood but couldn't find the suspects, and the attempted theft remains under investigation.
(Copyright 2013 by The Associated Press. All Rights Reserved.)