Ten of twelve species of wild ducks examined in central Saskatchewan were infected with renal coccidia. Of 261 ducks examined during autumn migration, 24.5% were infected while only 4% of 74 ducks examined during spring migration were infected. The greatest prevalence of infection occurred in female and juvenile birds. No gross lesions attributable to coccidia were found, and microscopic lesions were focal in nature. Oocysts from mallards were transmitted to captive mallards.