We used a randomized controlled trial and examined the effectiveness of a 3-month, home based, exercise program to the functioning in older Japanese adults. Following the intervention, we also conducted 3- and 6-month follow-up studies of physical functioning and exercise adherence. Participants were older adults (n = 32, 16 males and 16 females, age over 75 years). They were randomly divided into exercise and control groups. The Tokyo Metropolitan Institute of Gerontology Index of Competences, the Mini-Mental State Examinations, as well as physical fitness tests assessing grip strength, maximum step length, 10 m walking speed, and standing on one leg with eyes open were administered to the participants. Moreover, home visit instructions were given biweekly. Participants worked out at home on 3 days a week. Analyses of variance indicated that the intervention group significantly increased their maximum step length and time standing on one leg with eyes open, although there were no significant changes in the other tests. Result of follow-up investigations indicated that maximum step lengths at 3- and 6-months after the intervention were 69.9 and 68.8 cm respectively, which was less than immediately after the intervention (70.6 cm), but significantly higher than before the intervention (65.8 cm). Moreover, the effect of the intervention on standing on one leg with eyes open was maintained at the 6-month follow-up. Furthermore, percentages of participants that exercised more than one day per week 3- and 6 months after the intervention were 87 % and 81 % respectively, which was significantly higher than before the intervention (44 %). These results suggest that the home-based exercise program was effective in promoting adherence for a period of 6-months.