Helminth parasites of amphibians from the Gelegele Forest Reserve, a pristine forest in southwestern Nigeria, were investigated. Amphibians encountered included Amietophrynus maculatus, Hoplobatrachus occipitalis, Aubria subsigillata, Ptychadena longirostris, Ptychadena oxyrynchus, Ptychadena bibroni, Ptychadena pumilio, Chiromantis rufescens, Leptopelis hyloides, Hyperolius fusciventris and a Phrynobatrachus sp. Nineteen helminth parasites, including two cestodes, three monogeneans, six trematodes and eight nematodes were recorded from these amphibians. Contrary to the earlier assumption that monogeneans in Nigeria were preferentially parasites of amphibians in drier environments such as the savanna, this study has shown that these parasites also infect amphibians in highly humid environments such as the rainforest. Monogeneans recorded included Metapolystoma cachani and two unidentified Polystoma species. Haematoloechus aubriae, Mesocoelium monas, a Halipegus sp. and a Physalopteroides sp. are new geographical records for Nigeria.