Abstract
Encephalitozoon cuniculi was isolated from the urine of infected rabbits using human and canine tissue cultures. The organism was isolated from 7 of 11 contaminated urines from seropositive animals. The advantages of urine over tissue as a source of E. cuniculi are that it is obtainable from living animals, can be examined for the presence of organisms, and is essentially free of cells likely to overgrow the tissue cultures used for isolation.