Eight of 9 beluga whale (Delphinapterus leucas) in the Churchill River Basin were infected with Pharurus pallasii. The age range of infected whales was from under 1 year to 30 years. All adult infected animals had a large number of parasites in the accessory sinus, together with variable degrees of pulmonary granulomatous response. Histopathologic examination of lung revealed little host response to adult P. pallasii, but a strong inflammatory reaction to larval structures. Within the head, P. pallasii were found in the accessory sinus, ear canal and cerebral spinal fluid.