An inclusion-bearing cell is described which appears in the urine of patients with measles, german measles, chickenpox, mumps and herpangina. The presence of the inclusion-bearing cells in large numbers in the urine is very characteristic of measles, but not pathognomonic of that illness or viral disease in general. The possibility that the inclusions represent the cytopathic effects of viral infection on cells derived from the blood or urinary tract stroma is discussed.