Authorities say a passerby reported the odor in the 800 block of Michigan Avenue.
The Sheboygan Fire Department arrived on scene just after 5:15 p.m.
City records show the property is the site of the former Zurheide Ice Cream Co.
Authorities believe the leak came from the freezer compressor room in the basement of the property.
Crews worked to isolate the leak and monitor the surrounding neighborhood.
"The incident was resolved by 10:30 a.m. Sunday," Sheboygan Fire Battalion Chief Kevin Anhalt said. "I'm proud of how the crews handled the situation."
Chief Anhalt also stated that over 600 gallons of ammonia had to be pumped out of the tank. He said one of the seams in the tank had cracked, causing the leak.