To determine the factors that influence acute hospitalization among long-term home care patients, all patients (N = 59) who were provided home visiting nursing and/or medical care from a 169-bed community hospital in Saitama, Japan, between May 1989 and April 1993 were followed until November 1993. Data on patients concerning age, sex, diagnosis of primary disease, ability to perform activities of daily living (ADL), intellectual impairment, serum albumin, frequency of home visiting medical care, medical and nursing care provided at the patient's home were collected from the medical charts of each subject. The main outcome measure was onset of acute hospitalization during a one-year period after initiation of home visiting medical care. Thirty-five patients (59%) were admitted due to acute illness. Compared with patients who were not in need of acute hospitalization. Cox's proportional hazard model revealed that patients who were completely dependent for eating, dressing, and using the toilet (Hazard ratio (HR) = 3.13, 95% confidence interval (CI) = 1.34-7.35) and serum albumin less than 3.5 g/dl (HR = 3.05, 95% CI = 1.37-6.77) were more likely to be hospitalized. Evaluating a patient's physical conditions at the beginning of home visiting care may allow us to predict whether the patients will have to be hospitalized during the following one-year period.