Ironman is set to return to the Mad City each fall for the next six years.
The annual triathlon-race organizers announced Friday that the partnership with the city will extend through 2018.
The Madison Area Sports Commission chair, Vince Sweeney, said the agreement is another reason he considers Madison as a sports destination.
"The bigger win is really for all of us who live here," Sweeney said in a news release announcing the extended agreement. "We get to continue to host a world class athletic event [and] we also benefit from the significant economic impact that this event has on our area."
Organizers said the Ironman draws more than 45,000 spectators who line the course through rural areas and the downtown streets of Madison. In the fall event, athletes swim 2.4 miles in Lake Monona, followed by a 112-mile bike ride and a 26.2-mile run that finishes at the State Capitol, all without a break.
The Ironman Wisconsin race has been held in Madison for the last 12 years, the organization said.