Bahiagrass, Paspalum notatum Flügge, is an important forage grass in the southern United States. The species is native to South America where a number of different ecotypes and biotypes occur. ‘Pensacola', a sexual, cross-pollinated cultivar, has been widely planted in pastures and along the roadsides in the southern states. Consequently, the grass has spread and become naturalized throughout much of the southern U.S. In an effort to select types with more winter-hardiness, 16 accessions were collected at higher elevations in northern Arkansas. This study was undertaken to determine the amount of genetic diversity among these 16 accessions and to identify the bahiagrass cultivar from which they originated. Six bahiagrass cultivars and one plant introduction were also included. Significant genetic variation was identified across all accessions and cultivars based on amplified fragment length polymorphism analysis. This variation was illustrated in a dendrogram and by a low average genetic similarity coefficient of 0.57 across all accessions and cultivars. The 16 accessions tended to cluster together independent of the cultivars. DNA content of the accessions and cultivars was determined using flow cytometry. All 16 accessions were diploids, indicating they probably originated from Pensacola bahiagrass. However, these accessions are highly diverse when compared to one another and Pensacola. These findings reveal that genetic diversity occurs in naturalized bahiagrass populations as a result of cross-pollination and sexual reproduction.