Differing patterns of morbidity are demonstrated in a group of 181 foreign patients (from Turkey, Jugoslavia, Portugal, Italy, Spain) compared to an age matched group of native Germans hospitalized during a given time in the meidcal department of a regional urban hospital. In non-Germans peptic ulcers and severe infections more often lead to hospitalization than native patients. The expected statistical frequency of hospitalization is not different in the two groups investigated. Epidemiologic differences between the two populations are demonstrated by a higher percentage of tuberculosis and work accidents in the foreign group. At present there are no special obstetric problems leading to differing maternal or neonatal mortality. Concomitant imported infections do lead to complications in single cases in the foreign patient group. Parasitic infestation is more often found in the foreign group. Herditary diseases such as minor thalassemia or G-6-PD deficiency are rare as well in foreign patients. Chain infections due to imported poliomyelitis wild virus or salmonellosis have been observed in the foreign population. Epidemiologic progress may be highlighted by the decreasing percentage of hepatitis A and B antibody-positive-population in the central European countries.