Purpose: The purpose of this study was to investigate the effect of cancer-overcome BeHaS exercise program on pain, flexibility, grip strength and stress in patient with breast cancer following surgery. Method: Study was designed as a non-synchronized research method with a nonequivalent control group. Data collection was performed from September 2007 to January 1, 2008. Participants were 34 patients (experimental group: 19, control group: 15) undergoing surgery for breast cancer in a hospital in D city. Women in the experimental group were participated in the cancer-overcome BeHaS (Be Happy and Strong) exercise program for 60 minutes per session once a week for 8 weeks and it was recommended that they do the exercises once more each week at home. The control group received one education session on breast cancer management. Results: There were no significant differences between the two groups for pain, flexibility or grip strength. But stress in experimental group was significantly decreased compared to that of the control group. Conclusion: This result suggests that cancer-overcome BeHaS exercise program is helpful to reduce stress in patients after breast cancer surgery. Further research is needed for multi-dimensional evaluation on psycho-social effects of cancer-overcome BeHaS exercise program.