Two hundred five inpatients (age, 64.8±21.6 years ; mean±SD) were analyzed with respect to diagnosis, age, and complications to clarify the role of general internal medicine in large hospitals. The patients were divided into two groups: those younger than 40 years and those older than 40 years. In patients younger than 40 years, the most common diseases were viral infections, whereas a wide variety of diseases, including heart diseases, renal diseases, and neoplasms, were seen in patients older than 40 years. Disease in the older group were significantly more complicated than those in the younger group. we conclude that caring for older patients is good training for young residents learning general internal medicine.