The aims of this study were to confirm our previous finding that hormone-replacement therapy (HRT) augments exercise-induced increases in bone mineral density (BMD) in older women and to determine whether HRT preserves the adaptations when exercise is reduced or discontinued. The study included an 11-mo treatment phase and a 6-mo follow-up phase. Participants, aged 66 +/- 3 yr, were assigned to control (Con; n = 10), exercise (Ex; n = 18), HRT (n = 10), and Ex+HRT (n = 16) groups. HRT was continued during the follow-up. After the treatment phase, changes in total body BMD were -0.5 +/- 1.7, 1.5 +/- 1.4, 1.2 +/- 0.8, and 2.7 +/- 1.2% in Con, Ex, HRT, and Ex+HRT, respectively. Ex+HRT was more effective than HRT in increasing BMD of the total body and tended (P = 0.08) to be more effective at the lumbar spine. Ex+HRT was more effective than Ex in increasing BMD of the total body, lumbar spine, and trochanter. Exercise-induced gains in BMD were preserved during the follow-up only in those individuals on HRT. HRT also attenuated fat accumulation, particularly in the abdominal region, after the exercise program. These findings suggest that HRT is an important adjunct to exercise for the prevention not only of osteoporosis but also of diseases related to abdominal obesity.