Allozyme evidence shows that eastern Caribbean Eleutherodactylus assort into two distinct lineages. Species from northern islands (E. barlagnei, E. johnstonei, E. martinicensis, E. pinchoni, and Eleutherodactylus sp. A from Dominica) are a monophyletic group of Greater Antillean origin, whereas species from the southern islands (E. euphronides, E. shrevei, E. urichi) have South American affinities. Phenetic and cladistic analyses support sister-group relationships for E. barlagnei and E. pinchoni, and for E. euphronides and E. shrevei. Eleutherodactylus sp. A, E. martinicensis, and E. johnstonei are each other's closest relatives, but further resolution within this clade is confounded by their great biochemical similarity. The dual origin of eastern Caribbean Eleutherodactylus is best explained by "jump" dispersal, at least once from the Greater Antilles and once from northern South America. Dispersal from South America was most plausibly facilitated by the historic presence of a land bridge between Trinidad, Tobago and the Paria Peninsula of northern South America, and by rafting of individuals during the annual rainy season discharge of the Orinoco River into the Caribbean Sea.