Periodic quantitative surveys to monitor populations of freshwater mussels (Unionidae) were conducted at eight sites in the Verdigris River, KS during 1991, 1997, and 2003. Twenty-two species were collected including several on the Kansas rare-species list. Overall mussel abundance increased from 1991–2003. Abundance of 10 species (Cyprogenia aberti, Fusconaia flava, Lasmigona complanata, Pleurobema sintoxia, Ptychobranchus occidentalis, Quadrula metanevra, Quadrula nodulata, Quadrula pustulosa, Tritogonia verrucosa, and Truncilla donaciformis) increased significantly while only Lampsilis teres decreased. This positive trend in unionid abundance could be due to various factors that have improved habitat quality of this reach of river.