Little is known about specific clinical conditions that lead to hospitalization of nursing home patients. To explore this, the authors examined the hospitalizations of 128 nursing home residents and compared them with hospitalizations of 320 patients from the outpatient clinic. Hospitalized nursing home patients were older, were admitted to medical services more frequently, and had more nonspecific complaints on admission. Nursing home patients were hospitalized most frequently for diseases of the circulatory system (16 per cent), respiratory system (14 per cent), and genitourinary system (12 per cent); clinic patients, for diseases of the circulatory system (25 per cent) and nervous system (10 per cent), neoplasms (10 per cent), and signs and symptoms of ill-defined conditions (10 per cent). The most frequent causes of hospitalization for all patients were diseases of the circulatory system (23 per cent), nervous system (10 per cent), and neoplasms (10 per cent). Among patients from the nursing home, infections caused substantially more admissions (27 per cent) than among patients originating from clinic (12 per cent; P less than 0.001). These findings disclose an important opportunity to reduce health care costs and enhance quality of life in the nursing home, particularly through the treatment and control of infections.