During the fall of 1966 and spring of 1967, 260 cottontail rabbits (Sylvilagus floridanus) were collected from 13 sites in 8 southeastern states and examined for endoparasites. In order of prevalence, the endoparasites found were: Obeliscoides cuniculi, Trichostrongylus calcaratus, Trichostrongylus affinis, Taenia pisiformis (cysticerci), Raillietina salmoni, Eimeria spp., Longistriata noviberiae, Cittotaenia variabilis, Hasstilesia tricolor, Trichuris leporis, Dermatoxys veligera, Passalurus ambiguus, Dirofilaria scapiceps, Sarcocystis sp., Linguatula serrata, Nematodirus leporis, and Gongylonema pulchrum. Data are presented on prevalance and intensity of infection with each parasite along with information on geographic distribution. Cottontail rabbits in the southeastern United States show a higher level of parasitism than has been reported from other regions, although these higher parasite burdens were not necessarily associated with increased host morbidity.