The study carried out aboard a cruise ship in the years 1993-1998 involved ship passengers of various nationalities including 3872 Germans aged 23-94 years and 1281 Americans aged 25-94 years. Both nationality groups were divided into two age subgroups: till 64, and 65-94 years. The German younger age subgroup (mean age 53.2 years) consisted of 59% of the passengers, whereas the 65-94 years subgroup (mean age 72 years) was made up of 41% of the ships passengers. On the other hand, 73% of the Americans belonged to the 65-94 years subgroup (mean age 73,4 years), whereas 27% to the younger one (mean age 52.8 years). The number of onboard consultations and their causes were determined. The occurrence of chronic illnesses in both 65-94 years subgroups was assessed by means of a questionnaire. A higher frequency of consultations was found in the Germans (24.38%) than in the Americans (14.05%) (p=0.001). The difference was particularly striking in the people over 65 years of age (30.87% of the Germans as compared with 14.22% of the Americans, p=0.001). The Germans were nearly 4-times more frequently seen than the Americans for cardio-vascular diseases and almost 3-times more often because of gastrointestinal disorders. The discrepancies in the consultation rates were mainly caused by the different insurance systems of both nations. Chronic illnesses as estimated by means of the questionnaire prevailed in the German passengers. The statistically significant differences (13.3% versus 20%, p=0.01 and 0.001) regarded the locomotor system, urinary tract diseases and a group of illnesses including neurological, ophthalmological, ear, skin, malignant diseases and diabetes.