The house was built in 1915 for the president of a local insurance company. The building was believed to be a rare remaining example of Wright-designed architecture that was built by a short-lived Wisconsin fabricating company, American System-Built Houses, the Chicago Tribune reported.
A non-profit organization bought the house in 2000 and was in the process of renovating it. No one was hurt in the Monday night blaze, the report said.
It was the second fire in a week involving a Chicago area architectural landmark.
Last Friday, fire destroyed Chicago's Pilgrim Baptist Church designed by architect Louis Sullivan.
On Monday, Illinois Gov. Rod Blagojevich pledged up to $1 million in state funds to rebuild the church's school and offices in the historic Bronzeville neighborhood on Chicago's South Side.