Rapid deforestation in the tropics is resulting in the extinction of many species. This problem is compounded in the West Indies by the limited distributions of species and an ever increasing human population. West Indian amphibians and reptiles (>570 sp.) are especially susceptible to extinction because most species are restricted to small areas within each island. New species continue to be discovered at a high rate indicating that our knowledge of the actual species diversity is incomplete. Cuba and Hispaniola are the two largest islands in the West Indies, harbor the greatest number of species, and have the least known amphibian and reptile faunas. The first goal of this research is to document the existing species diversity of amphibians and reptiles by conducting exploratory field studies in poorly known regions of Cuba and Hispaniola. This aspect involves the formal scientific description of new species as well as studies that provide new or corrected information on previously described species. The second goal is to use modern genetic techniques to uncover the genealogical relationships of the species. This information is valuable for testing existing theories and developing new ones in the field of evolutionary biology. It will also help in understanding how the many species of plants and animals inhabiting the islands of the West Indies originated.