An inventory of the bee fauna of Prairie State Park was conducted from May through October in 2003 and in April 2005. The1,642.5 hectare park is located in Barton County and protects the largest remaining stand of tallgrass prairie in Missouri. A total of 68.4 hours of sampling was conducted with an aerial net on twenty different dates. Seventy eight species of bees from six families and nine genera were represented on the preserve. Twelve species (15 % of the fauna) were parasitic on other bees. Floral visitation records and flight seasons are reported.