The Ninety-Ninth Wisconsin Legislature convened from January 5, 2009, through January 3, 2011, in regular session, though it adjourned for legislative activity on May 26, 2010. The legislature also held two special sessions and four extraordinary sessions during this legislative term.

The Ninety-Eighth Wisconsin Legislature convened from January 3, 2007, through January 5, 2009, in regular session, though it adjourned for legislative activity on June 11, 2008. The legislature also held five special sessions during the term.