A 5-year cohort study was conducted to determine factors that predict the institutionalization of elderly people who reside at home in a geographically-defined rural community in southern Japan. Among 766 (321 men and 445 women) residents living at home, 742 (97%) were followed-up for 5 years. During that period, 55 (25 men and 30 women) subjects were institutionalized. In univariate analysis, institutionalization of men was significantly associated with incontinence (either urinary or fecal), speech impairment, impairment in activities of daily living (ADLs: transferring, eating, dressing, bathing), being housebound, and the use of a commode. In women, it was associated with incontinence, visual impairment, ADLs impairment, being housebound, and the use of a commode. Using Cox regression hazard model analysis, incontinence was identified as a predictor for institutionalization in men, but not in women. In women, visual impairment was a predictor for institutionalization. The use of a commode and the other variables had no association with institutionalization in either sex. In conclusion, incontinence is a predictor for institutionalization in elderly men. Use of a commode, however, does not appear to have a preventive effect with respect to institutionalization in elderly men.