Objective: To assess the clinical efficacy of the modified radical mastectomy with first-stage breast reconstruction using extended latissimus dorsi flap in treatment of breast cancer. Methods: The clinical data of 150 patients with breast cancer undergoing total mastectomy from March 2008 to March 2013 were retrospectively analyzed. Of the patients, the traditional modified radical mastectomy was performed in 28 cases, skin sparing total mastectomy was performed in 47 cases, and nipple sparing total mastectomy was performed in 75 cases, and all of the cases received synchronous breast reconstruction using extended latissimus dorsi flap. Results: The operation was performed successfully in 149 patients and failed in one patient. The excellent/good rate of the appearance evaluation of the reconstructed breast reached 91.27% (136/149). After surgery, partial nipple necrosis occurred in 4 patients, and chest skin contusion with exfoliation occurred in 3 patients, all of which healed spontaneously without special treatment; dorsal hematoma occurred in 8 patients, of whom 6 cases resolved by puncture and aspiration, one case was cured by removal of the fibrous capsule, and one case was cured after resection of the sinus tract and false membrane; local skin necrosis at the margin of wound occurred in 2 patients, and partial necrosis in the donor region of the flap occurred in 2 patients, which were resolved by a second surgery; ischemic necrosis of the graft occurred in one case, which was treated by surgical resection. Followed-up was performed for 8 to 73 months (18 patients were lost to follow-up, all of whom had disease-free survival before lost to follow-up), during which time, 2 patients developed bone metastases, one case each developed pulmonary metastases and supraclavicular lymph node metastases, and no local recurrence occurred in any of the patients. Conclusion: Modified radical mastectomy with first-stage breast reconstruction using extended latissimus dorsi flap in treatment of breast cancer is safe and effective, and is especially suitable for the patients with small or medium breast size.