Agricultural land use is one of the drivers of amphibian decline and it also impacts on the severity of amphibian parasitism. As part of our investigations of the effect of land use on biodiversity and parasitism, we studied the helminth parasitic infections of tree frogs from the High Conservation Value Area (HCVA) at the Okomu Oil Palm Plantations located in Oke Community, Edo State, Nigeria. The frogs were identified, euthanized and then dissected. The gastrointestinal tract and other organs of the viscera were examined for parasites. Ten species of tree frogs were encountered at the HCVA from which seven platyhelminth and three nematode species were recovered. Notable among the parasites was a tetracotyle strigeoid larva, which is a new parasite record in Nigeria. The number of tree frog species and the number of helminth parasites recovered at the HCVA was low when compared with the records at the Okomu National Park. Habitat fragmentation and loss of adequate canopy cover have negatively impacted on tree frog diversity in this sanctuary. Although the HVCA did not provide adequate cover for tree frogs, the idea of a conservation area in the midst of oil palm plantations is desirable and should be encouraged.