In 1973/74 in the district of Traunstein a study was conducted which, like a corresponding study in Mannheim, aimed at the determination of the frequency of mental disorders among patients in general practices. Three research psychiatrists evaluated 1.274 patients in 18 general practices by means of an interview developed by Goldberg et al. (1970) and diagnosed patients according to the ICD (International Classification of Diseases). The study was based on a representative sample of all patients who consulted a physician during a 14-day period. About 1/3 of all patients (32%) showed psychiatric symptoms according to the evaluation of the interviewers, but only about 1/4 (26%) according to the opinion of the general practitioners. The bulk lies in neurotic and psychosomatic illnesses, comprising more than half (57%) of the mentally ill. About 10% each are listed for psychogeriatric disorders, affective and other psychoses as well as personality disorders. The results largely coincide with those for comparable studies in Mannheim and Norway.