The 11 p.m. robbery happened behind the 1200 block of West Argyle Street, near Argyle and Magnolia, said police.
Investigators said two black males, one armed with a gun, approached the victim and stole a wallet containing $1000.
The gunman is about 5’10” and 200 pounds. He was wearing a dark red or purple shirt and blue jeans.
The stickup man’s accomplice was wearing a dark-colored shirt and blue jeans.
After the robbery, the thieves fled eastbound through the alley.