On December 26, a challenge was filed to the petitions submitted to place Chicago Mayor Richard M. Daley on the ballot. Chicago requires 12,500 signatures for anyone to get on the ballot in any citywide race. The elections have been non-partisan starting in 1999. Before 1999, Democrats and Republicans needed far fewer signatures, whereas everyone else needed 25,000.

Mayor Daley submitted 24,000 to meet the requirement of 12,500, so it is unlikely that the individual who challenged his petition will be able to show the petition is invalid.

The election is February 27, 2007. Five candidates for Mayor filed petitions; three of those five are being challenged.