Three suspects broke the side glass door at Big League Burgers, located at 3734 W. Irving Park Road in Irving Park, about 4:15 a.m.
The suspects entered the restaurant, and stole cash from the registers, police said.
They then got into a silver sedan, and drove west, CPD said.
No one was in custody later Tuesday, and Area Five detectives are investigating.
This isn't the first time Big League Burgers has been broken into.
One of the owners said there have been at least two previous break-ins at the family-owned business within three years.
He's hoping some kind of change can happen to help small business owners like him.
Early Tuesday morning, Peter Mihopoulos says he got an alert about activity detected at the restaurant.
"All of a sudden, I just see the registers on the floor, and I see people breaking in from the side, running through the restaurant and back, right now," Mihopoulos said.
Surveillance video captured the suspects breaking in.
Mihopoulos says the group used a brick to smash open a side door before they stole whatever they could.
They wore hoodies and masks.
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They were in and out in less than 30 seconds.
Mihopoulos said he felt helpless watching this all happen through his security cameras.
"I just saw the alert on my phone, and I'm like, 'it can't be happening again,' and it happened," Mihopoulos said.
Mihopoulos says his restaurant was broken into last April and in November of 2022.
The April break-in was similar. In November of 2022, burglars smashed through the front door.
The suspects in those incidents ransacked the office, in addition to taking money from the registers.
This time he hopes changes can be made to better protect small business owners.
"Everybody has to step up as a group from the top, to the mayor, the governor, alderman, representatives from the city, Illinois. They just have to come as a group together to try to fix what once was a great city," Mihopoulos said.
The restaurant survived opening in the pandemic.
He said burglaries should not be the cost of doing business in Chicago.
The damage from the most recent break-in will take thousands to repair, he said.
"We just need everybody's support, to get back to going and see another day," Mihopoulos said. "You put something together with your heart and try to make it good for everybody, every day, and it's tough seeing what's going on."