We qualitatively surveyed freshwater mussels in the Salt River basin, Missouri, during 1977–86 and 2005–7. A cumulative sample of 6,234 live individuals representing 31 species was recorded during both periods; six additional species were recorded only as shell material. Amblema plicata was the dominant species recorded, representing 31.3% of the total live animals. There were no significant differences in average species richness values, Brillouin's index values, or relative abundances of the tribes amblemini-pleurobemini-quadrulini between the two surveys. The most notable change was the complete loss of the mussel fauna in the South Fork Salt River. We also observed significantly higher probabilities of local extirpation in the mainstem Salt River, North Fork Salt River, Middle Fork Salt River, and South Fork Salt River. At the tribe level, the amblemini had a higher probability of local colonization and the lampsilini had a higher probability of local extirpation.