Police are looking for four suspects in the attacks. Officials say they would surprise their victims by yelling at them and then attacking them.
All of the victims are young men between the ages of 22 and 27. One of them remains hospitalized with a broken jaw and throat injuries, police said.
The robberies occurred in the early morning hours and involved people walking alone in the North Side neighborhood. In all four attacks, the victims' phones and wallets were taken.
The first attacks occurred Wednesday in the early mornings. The most recent attacks occurred Saturday: at 3 a.m. a man was attacked and robbed in the 2000-block of North Cleveland; and at 3:30 a.m. another man was beaten and robbed in the 300-block of West Webster.
In one of the attacks, police said the victim figured out what was going to happen so he threw his wallet down. He was still beaten.
"People are going to be looking over their shoulders and maybe not going out as much," said Nada Riley, president, Mid North Association
"I'm always cautious about my surroundings. I'm always aware of looking to see if I need to be aware or need to cross the street," said Joel Brillant, neighborhood resident.
Ian Watkins said his friend had an iPhone stolen last week.
"This guy came around. Joggers outfit, the whole nine, and just snagged his phone right out of his hands. It was probably around right when it starts getting dark," said Ian Watkins, neighborhood resident.
Alderman Vi Daley urges caution if people are going to be out late.
"Don't travel alone. If you are out, make sure you're with somebody. And if you've been drinking too much or even you don't have to be drinking, but out late at night, hop in a cab," said Ald. Vi Daley, 43rd Ward.