Onchocerca tarsicola is recorded from reindeer (Rangifer tarandus L.). This parasite is originally described from red deer (Cervus elaphus L.). There are indications that reindeer may not be the primary host of O. tarsicola: 1. Reindeer is parasitized only by O, tarsicola whereas red deer, due to speciations, is carrying three related Onchocerca species from the same line. 2. O. tarsicola, usually found along tendons distal of the tarsal and carpal joints, is in reindeer frequently found at aberrant locations which is commonly observed in connection with transfuga" parasites. 3. Heavy infestations of O. tarsicola in reindeer seem to have started in the late sixties and since then have become more and more extensive."