This study was conducted to identify the effects of exercise therapy applied in an efficacy expectation promoting program that was based on Bandura's self efficacy model on self-efficacy, cardiopulmonary function and metabolism in type 2 diabetes mellitus patients. The study design was nonequivalent pre-test post-test control design. 34 type 2 diabetes mellitus patients who received follow-up care regularly through the diabetic out-patient clinic were randomly sampled for this study. Twenty patients were assigned to the experimental group and fourteen patients were assigned to the control group. To the experimental group, exercise therapy applied in an efficacy expectation promoting program that is composed of individualized exercise prescription for 12 weeks was provided. In case of the control group, they were instructed to continue their usual lives. Data collection period was from March 1998 to June 2000 Data were analyzed using SPSS/WINDOW 10.0 program. The results were as follows. In experimental group. The score of self efficacy has increased from 64.20 to 66.65 after exercise therapy applied in an efficacy expectation promoting program and it was statistically significant(t=2.07, p=.04). The anaerobic threshold has increased from 18.20 ㎖/kg/min to 19.07 ㎖/kg/min and it was statistically significant (t=2.05, p=.04). Level of fasting blood sugar has decreased from 188.20 mg/㎗ to 155.55mg/㎗ after exercise therapy applied in an efficacy expectation promoting program and it was statistically significant.(t=-2.69, p=.01). For the lipid metabolism, percent body fat has decreased from 27.16 % to 26.57 % after exercise therapy applied in an efficacy expectation promoting program. In conclusion, the exercise therapy applied in an efficacy expectation promoting program showed positive effect on self-efficacy, cardiopulmonary function and glucose and lipid metabolism.