Three men were standing outside about 12:10 p.m. when someone fired shots at them in the 500 block of North Leamington Avenue, Chicago police said.
One man, 64, was struck in the leg, and another, 54, was struck in the thigh, police said. Both were taken to Mt. Sinai Hospital in critical condition.
The third man, 42, was grazed on the back, police said. He was treated at the scene.
Later, a fourth person showed up at Loyola University Medical Center in Maywood with a gunshot wound to the shoulder, police said. He was in good condition.
No one is in custody as Area Five detectives investigate.