All guests will now go through a screening process when they arrive, including a temperature check.
Inside, around every other slot machine and sports book kiosk will be turned off to help enforce social distancing. Employees will all be in masks and you won't be able to get a drink on the casino floor.
In northwest Indiana alone, casino re-openings could help more than 5,000 workers who reportedly lost their jobs when the pandemic shut business down earlier this year.
Indiana has racked up nearly $200 million in tax revenue losses as a result of the closures.
Cynthia Staras was first in line Monday morning at Majestic Star Casino and eager to play the slots again.
"They are going to check everybody's temperature, give you some kind of healthcare kit or something, I don't know what that is yet, but they are doing their part to keep everybody safe but everybody else has to do their part."
"We've been waiting for a while and we haven't had this much fun in a while," Patrick Barron said. "Been cooped up inside the house way too long."
ABC7's cameras were not allowed inside Majestic Star Casino. A spokeswoman said it was just too busy to accommodate the request.
In addition to casinos opening, the state gaming commission is also allowing charity gaming to resume Monday, which means activities like church bingo are back as well.
The Majestic Star Casino in Gary isn't the only Chicago area casino opening Monday. The Hammond Horseshoe also opened at 6 a.m., where visitors started the process to enter with a temperature and ID check.
A spokeswoman for the casino emphasized that mask wearing is strongly urged, as is social distancing.
In at least one line observed by ABC7, social distancing was not apparent despite a request by an employee.
Some coming out of the casino said that once they were inside, they did feel comfortable.
"I felt safe there," Patt Beaulieu said. "There was hand sanitizer, you wait at the elevator three at a time, walk through a long hallway, check your ID and then you can go and gamble as long as you want."
"The machines were distant," Diana Shelton said. "You might have a whole row of machines and then one on the end is where you would play one end and the others have signs on them."
While Horseshoe resumes its regular hours, a casino spokeswoman said that capacity is reduced by 50 percent for now.
Indiana health officials say the state has 11 additional deaths due to COVID-19 and 533 new cases. The Indiana State Department of Health announced there have been a total of 2,251 coronavirus deaths overall since the start of the pandemic and 40,430 total cases in the state.
Health officials say there are another 182 probable deaths with no positive test on record.
Effective Monday, any Hoosier seeking COVID-testing can obtain it through one of the state-sponsored OptumServe sites, regardless of whether they are at high risk or have symptoms.
To find testing locations around the state, visit www.coronavirus.in.gov and click on the COVID-19 testing information link.
The Associated Press contributed to this article.