Twelve species (Bothriopsis bilineata, B. oligolepis, B. taeniata, Bothrocophias microphthalmus, Bothrops andianus, B. atrox, B. jonathani, B. moojeni, B. neuwiedi, B. sanctaecrucis, Crotalus durissus, Lachesis muta) and five genera of pitvipers are known from Bolivia. Known ranges of several species are expanded to accommodate recently collected material and Bothrops andianus is reported from Bolivia. The holotypes of Bothrops andianus and Lachesis peruvianus are redescribed. Bothriopsis oligolepis (Werner) is shown to be synonymous with Lachesis peruvianus Boulenger rather than L. chloromelas. We designate a lectotype of Bothriopsis chloromelas (Boulenger) and apply this name to the ornately patterned forest pitviper endemic to the northern and central Andes of Peru. Morphological variation and reproductive data are reported for B. sanctaecrucis. References to Bolivian specimens of B. jararacussu are based on misidentifications of B. sanctaecrucis. Although the known ranges of B. brazili, B. jararacussu, and Bothrocophias hyoprora approach Bolivia's borders, these species have not yet been collected within the country. A rectangular loreal is rare in pitvipers and may be a synapomorphy of two small Andean pitvipers: B. andianus and B. lojanus.