This study examined the efficacy of a group‐mediated cognitive behavioral intervention (GMCB) on adherence rates to physically active lifestyles in older adults. Sixty older adults were randomized to I of 3 groups: waiting list control (WLC), a standard physical activity program (SPA), or GMCB. The SPA and GMCB involved 6 months of combined center‐ and home‐based activity. Contact with participants was then terminated with a follow‐up assessment at 9 months. Results revealed that, at the 9‐month follow‐up the GMCB group had a higher frequency of weekly physical activity than the SPA group. At 6 months, both groups were more active, had higher aerobic power, and improved HRQL when compared with the control group.