Until recently reliable information on the prevalence and courses of psychological disorders in primary care was largely lacking. Due to the development of standardized psychiatric interviews and reliable diagnostic classifications, this situation has improved considerably. This paper describes these developments and presents an overview of research findings regarding prevalence, course and factors which influence the course of minor psychiatrie disorders. As prevailing diagnostic classifications are no great help to the general practitioner with his limited choice of treatment, the authors argue in favor of the development of a multi-axial classification which is adapted to the conditions in primary care. Such a multi-axial classification takes into consideration not only psychopathology, but has also axes or dimensions on which the level of social functioning, personality features and psychosocial stressors can be coded.