Mastectomy is recommended for ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery plus radiotherapy(breast-conserving treatment). However, the number of patients who receive radiation therapy such as breast- conserving treatment in the hope of breast reconstruction is increasing. Radiation therapy has a significant magnifying effect on the difficulties of breast reconstruction. In the study presented here, we compared the patients who underwent mastectomy+ breast reconstruction with a tissue expander and an implant after IBTR and breast-conserving treatment (irradiation group, n=5) with patients who underwent mastectomy+breast reconstruction with a tissue expander and an implant at the time of the first breast cancer operation (non-irradiation group, n=21). The parameters compared were background, complications, reconstruction success rate, and capsular contraction. A significant difference was not observed between the 2 groups. Complications after operation, specifically capsular contracture, are reported to be more frequent in the radiation group than in the non-irradiation group. However, with appropriate explanation of the risks, this surgery is an option for patients who strongly desire breast reconstruction.