PURPOSE: This study was to examine the effect of postpartum exercise on mental health. Mental health comprises a 9 symptom dimension of Somatization, Obsessive-Compulsive, Interpersonal Sensitivity, Depression, Anxiety, Hostility, Phobic anxiety, Paranoid Ideation, and Psychoticism. METHOD: A non-equivalent pre-test, post-test control group study was conducted. Fifty-two puerperal women who were admitted to a postpartum ward of a mother-baby clinic in Pusan were recruited; 26 women were assigned to the experimental group and 26 women to the control group. Postpartum exercise was applied to the experimental group from postpartum day 3 for a period of 8 weeks while no exercise program was applied to the control group. Mental health with SCL-90-R was measured before and after exercise. Data was analyzed using mean, x2-test, t-test, and ANOVA by SPSS 10.0. RESULT: The mental health status in the exercise group did not show a statistically significant decrease when compared to that of the control group. CONCLUSION: There is no effect of postpartum exercise on women's mental health during the first 8 weeks of the postpartum period. Further studies are needed for randomized clinical trials with a larger sample size.