A survey of persons in treatment for psychiatric disorders with the general practitioners of an island showed a one–year prevalence rate of 51.5 per thousand population. This represents more than twice the rate of those who consult a psychiatrist in the same community during a year, even though psychiatric service is readily available, geographically accessible and of low cost. Thus, even under these conditions, the larger burden of treating psychiatric patients was being borne by the general practitioner. In nine of every ten patients, the problem was a psychoneurotic, psychophysiologic or personality disorder. Alcoholism was present in 28 per cent of all males considered to have psychiatric conditions. The psychiatric disorder rates were 50 per cent higher in the never–married and separated–divorced–widowed groups than in married people. Data on prevalence in relation to social class are provided also.