Inside the packed church, firefighters, family members, and friends honored the men and women lost this year as part of an 80-year tradition in Chicago.
A bell tolled for each life lost, including Captain Herbie Johnson, who was killed while fighting a fire, and Walter Patmon, Jr. who went into cardiac arrest hours after fighting a fire.
Their families and the families of many others use the Memorial Day mass to honor their loved ones.
"My father passed away July 14th and he was a Chicago fireman, and my brother is a Chicago fireman, and I worry about him all the time, too," said Pam Hormanski. "It's a wonderful ceremony to acknowledge their existence."
Charlie Boyd, a retired lieutenant with the Chicago Fire Department, has been taking part in the service for 40 years.
"It's a brotherhood, and I lost a nephew this year," said Boyd. "It's in my heart."
After mass, there was a 21-gun salute, and bagpipes played in front of uniformed fire department members.