Forty-one children who were being treated in a paediatric clinic for enuresis were studied to see how many of them were psychiatrically disturbed on clinical assessment and to ascertain the usefulness of 2 cut-off points of T (total) scores on the Rutter A Scale in identifying them. A score of 13 or more which had previously been recommended was found to be inadequate in this group of cases. There were indications that a cut-off point of 18 or more was more appropriate. The importance of knowing the base rate of psychiatric disorder in the population on which the questionnaire is being used is emphasized, sinec this affects the selection of an appropriate cut-off point.