During 1980 to 1982, parasitological surveys were carried out at large impoundments in Venda and Lebowa, southern Africa, coinciding with fish harvesting programmes. Of the various fish species examined, onlyOreochromis mossambicuswas found to be infected byClinostomum tilapiaeprevalent in the gills, andEuclinostomum heterostomumprevalent in the muscles. Distribution records and infection statistics are presented for these two parasite species.