Experimental transmission of canine encephalitozoonosis was effected by oral dosing of urine obtained from naturally diseased animals. Per os, intraperitoneal and intravenous routes were used to induce infection with tissue culture-grown Encephalitozoon spores which were initially isolated from the kidney of a dog with terminal disease. The infection was confirmed by a rise in the indirect immunofluorescent antibody titres, the lesions found in infected dogs and isolation of the parasite in tissue culture from an infected and immunosuppressed dog. The experimentally induced disease was invariably subclinical but the histopathological changes were similar although milder than those found in fatal natural disease. The kidney appears to be the target organ and chronic interstitial nephritis develops regularly.