In this 12-month trial standard exercise training was compared with a group-mediated cognitive-behavioral (GMCB) intervention with respect to effects on long-term adherence and change in physical function of older adults who were either at risk for or had cardiovascular disease. Participants (147 older men and women) were randomized to the 2 treatments. Outcomes included self-reportedphysical activity, fitness, and self-efficacy. The GMCB treatment produced greater improvements on all outcomes than did standard exercise therapy. Regardless of treatment assignment, men had more favorable change on the study outcomes than did women. Analysis of a self-regulatory process measure in the GMCB group revealed that change in barriers efficacy was related to change in physical activity and fitness. Results suggest that teaching older adults to integrate physical activity into their lives via GMCB leads to better long-term outcomes than standardized exercise therapy.