Purpose: This study was conducted in order to investigate the effects of an aerobic exercise program on mobility, fall efficacy, balance, and stress in the elderly at senior centers. Methods: This research was conducted as a quasi-experimental pretest and posttest control and experimental comparison study. The subjects were 41 senior residents (Exp.=18, Cont.=23) who aged above 65 at senior centers in S City. The period of time for data collection and intervention was from August 25 to December 5, 2008. Results: Mobility (t=-3.10, p<.01) in the experimental group were significantly higher than those in the control group without an aerobic exercise program. However, fall efficacy (t=1.28, p=.207), balance (t=-.53, p=.602; t=.36, p=.723), stress (t=-1.32, p=.199) in the experimental group was not significantly higher than that in the control group. Conclusion: These findings confirmed that aerobic exercise programs make a contribution to improving mobility in the elderly at senior centers.