Two species of ranid frogs, Lithobates taylori and Lithobates vaillanti, from Costa Rica were examined for helminth parasites. Three species of Digenea, Gorgoderina megacetabularis, Gorgoderina parvicava, Haematoloechus meridionalis and three species of Nematoda, Oswaldocruzia costaricensis, Subulascaris falcaustriformis, Porrocaecum sp. (larvae) were found in Lithobates taylori. All represent new host records. Five species of Digenea, Glypthelmins facioi, Gorgoderina megacetabularis, Haematoloechus meridionalis, Langeronia macrocirra, Loxogenes arcanum, four species of Nematoda, Contracaecum sp. (larvae), Foleyellides striatus, Physaloptera sp. (larvae), Subulascaris falcaustriformis, and two species of Acanthocephala (centrorhynchid and oligacanthorhynchid cystacanths) were found in Lithobates vaillanti. Loxogenes arcanum, Contracaecum sp., Physaloptera sp., oligacanthorhynchid cystacanths represent new host records.