The Child Psychiatric Clinic of the Paediatric Department at St. Thomas' Hospital has had a relatively large number of referrals of disturbed children under 5 years of age, because of the existence of a day hospital where they and their families can be offered treatment together (Frommer, 1967). As there are few reports on psychiatric disturbance in this age-group, we thought it worthwhile to report on some aspects of their problems as we have seen them. Clinical experience led us to the supposition that we would find recurring patterns of family disturbance and symptoms accompanying the main behavioural disturbances for which they were brought. For this reason, we undertook an analysis of the presenting features, symptoms, behaviour, and family circumstances of all pre-school children who were referred to this Clinic during six years from August, 1962, when the day hospital first opened as a part-time pilot venture, to August 1968. The following is an account of some of our findings.