The fire took place in a three-story building at Eureka Apartments in the 1600-block of South 50th Court at about 6:30 a.m., fire officials said.
The fire started in a second floor apartment and spread to the back of the building, consumed the back wooden porch and spread to the third floor.
Two residents, a man and a woman, were transported to hospitals with minor injuries. Firefighters also rescued six cats.
"This is a terrible fire that could have done far more damage to lives and I am just proud of how fast the firefighters got there to constrain fire," said Cicero Fire Chief Dominick Buscemi.
Cicero officials are working with the families to find temporary housing.