PURPOSE: This study aims at confirming exercise effects on obesity, mobility, self-efficacy, process of change, and decisional component by stage based exercise motivational intervention program for the elderly. The stage based exercise intervention program was constructed based on Transtheoretical Model. METHODS: The design of this study is nonequivalent control group with repeated measuring by quasi-experimental study. The subjects of this study, composing of experimental group of 32 and control group of 28 were selected at one institution for the aged in Seoul. RESULTS: 1) The body fat (weight, BMI and circumference of waist), of the intervention group was significantly decreased than the control group. 2) The mobility of the intervention group was not significantly increased than control group. 3) The self-efficacy, Pros, Process of Change for exercise of the intervention group was not significantly increased than the control group. 4) The Cons for exercise of intervention group was not significantly decreased than the control group. CONCLUSION: The above result have informed us that a stage-based exercise motivational intervention program for the elderly has the effect of decreasing old persons' body fat and has value as an effective means of nursing for the elderly.