Thirty-four anuran species in Comoé National Park, Ivory Coast (West Africa), were checked for infestation by larvae of the intradermal chigger mite, Endotrombicula pillersi (Acarina: Trombiculidae) for 5 y (1991–1995). Endotrombicula pillersi is a species-specific parasite of Phrynobatrachus francisci (Anura: Ranidae) at this site. Up to 84% of these frogs had irregular red excrescences on their ventral side, the typical symptom of chigger mite infestation. None of the other 33 sympatric anuran species was infested, with the exception of 1 individual of Bufo maculatus (Anura: Bufonidae). Local populations of P. francisci had a similar prevalence of mites in successive years, with nearby populations showing considerable differences between 1 and 227 larval mites/host. The encapsulated larval mites were densely clumped on the ventral side of the legs and near the cloacal opening of frogs. High intensities of up to 100 parasites/host caused pathological effects. Such as necrosis or rectal prolapsus. We found no change in number and position of larval mites, nor any pathological effects, in frogs with low intensities of infestation that were kept in terraria up to 3 y. Histological examinations demonstrated that the lining of capsules surrounding embedded mites consisted of connective tissue of the host dermis. Both the gnathosoma and extremities of the larval mites were embedded in the tissue of capsules.