This paper reports a survey of psychiatric morbidity in a semi-urban community (population 7,653) in Sri Lanka. The entire population was first screened by social workers using a standardized interview. Probable cases were then examined by psychiatrists. Each psychiatric disorder identified was rated on four different parameters of severity, and only those rating moderate or severe were labelled as cases. The socio-demographic characteristics of the cases and the population at risk, and the frequency and nature of psychiatric disorders are presented in Tables. The 6-month period prevalence for all psychiatric disorders was 45.5 per 1,000, with psychoses amounting to 6.9 (males 5.5; females 8.4) per 1,000, and neuroses to 25.2 (males 9.9; females 40.6) per 1,000. The large majority of disorders were chronic and had not received psychiatric treatment. The relevance of these surveys in the provision of psychiatric services in developing countries is discussed.