In each incident, someone armed with a knife approaches a pedestrian on foot and demands their belongings, police said.
After taking their belongings, the suspect flees the scene.
The first robbery took place at 12:30 a.m. on Sept. 11 in the 4600 block of North Kasson Avenue.
The next robbery happened four days later at 12:21 a.m. in the 4700 block of North Kilpatrick Avenue.
Anyone with information on these robberies is asked to contact Area Five detectives at (312) 746-7394.