Survey results indicate more mental health problems among immigrants than in the native population in Sweden and in one country of departure, Finland. This is reflected in the high proportion of immigrants in the mental hospital studied, but not among psychiatric out-patients. The immigrant patient rate is high even in socially advantageous groups, eg. among married and employed persons. The diagnoses and problems reported in the patient case records of immigrants and natives are compared, with controls for background variables. Some problems, e.g. paranoia, somatic symtoms, and diffuseness of difficulties are clearly related to immigration status but others, eg. alcohol, work, or human relations problems are connected only with social class or sex, irrespective of immigration status.