 
The 2008 Wisconsin Senate election was held on Tuesday, November 4, 2008. Sixteen of the 33 seats in the Wisconsin Senate were up for election—the even-numbered districts. Prior to the election 17 seats were held by Democrats, 14 were held by Republicans, and 2 seats were vacant.
The primary was held on September 9, 2008, and the filing deadline was July 8, 2008.
Summary.
Close races.
Seats where the margin of victory was under 10%: