A faunal and diversity analysis of the Dytiscidae of St. Catherines Island, Georgia, was conducted from 1997 to 2003. Collections from 10 localities were made with a total of 1143 specimens representing 23 species. The three most abundant species were Bidessonotus inconspicuus, Desmophachria grana, and Desmopachria convexa; all other species were represented by fewer than 83 specimens. Specimen size ranged from 1.5 mm to 15.8 mm; species less than 2.69 mm predominated at six of the 10 localities. The Shannon diversity index varied from 0.84 to 1.96 and the Brillouin diversity index varied from .78 to 1.82. Since both indices are sensitive to sample size, rarefaction analysis also was employed. Using this approach all localities except one had the species richness expected based on sample size. Overall the fauna was represented by a few common species and numerous rare species.