Background: In cases of mastectomy for locally advanced breast cancer (LABC), surgical skin flap reconstruction is sometimes required to cover large skin defects. In this study of patients with LABC, the patient group that required local flap reconstruction after mastectomy and the patient group that underwent mastectomy alone were compared to evaluate the efficacy of local, cutaneous (rhomboid) flap reconstruction after mastectomy. Methods: Sixty-eight patients with LABC who underwent mastectomy were reviewed retrospectively. Fourteen patients underwent local (rhomboid) flap reconstruction after mastectomy (local flap group) and 54 patients underwent direct closure after mastectomy (direct closure group). A pinch test was performed to determine the closure method. Data regarding the operation and post-operative complications and quality of life (QOL) were compared between both groups. Results: It was possible to close defects in the local flap group that were significantly larger than those in the direct closure group (p=0.0002), and there were no significant differences in post-operative complications between the groups. Although the operative duration was significantly longer in the local flap group than in the direct closure group (p=0.016), the average difference was only 25 minutes. There were no significant differences in factors pertaining to post-operative QOL. Conclusions: Rhomboid flap reconstruction is effective for covering large defects after mastectomy in patients with LABC.