Prescribed fire is used to reduce coverage of woody vegetation in early successional habitats, but burning may also result in direct and indirect mortality of reptiles inhabiting the burn site. Mowing prior to burning has been hypothesized to render grassland habitats unsuitable for the massasauga (Sistrurus catenatus), thereby reducing the number of individuals that may be affected in the management unit at the time of burning. I evaluated the impact of mowing prior to summer burning on massasaugas at Squaw Creek National Wildlife Refuge, in northwestern Missouri, during the summer of 2003 using radiomarked snakes. Pre-burn mowing resulted in the direct mortality of three (43%) of seven radiomarked massasaugas present in the treatment area. Prescribed fire resulted in a mortality of one of two remaining individuals. Pre-burn mowing did not reduce mortalities as hypothesized and likely added to the overall snake mortality rate. Management alternatives other than mowing and prescribed fire when snakes are active should be considered when managing massasauga habitat.