The study was conducted to determine if parasite load was related to the age of the host. A total of 127 incidentally caught Dall's porpoises, Phocoenoides dalli dalli, were necropsied aboard a Japanese salmon factory ship. The incidence of three parasites, Campula oblonga, Halocercus dalli, and Crassicauda sp. were recorded. The occurrence of hepatic trematodiasis appeared to increase with the age of the host. The incidence of pulmonary nematodiasis and nematodes found in the mammary gland did not appear to be age related.