Breast cancer is the most frequent cancer in women. Acute postoperative pain after breast cancer surgery (BCS) is an integral risk factor in the development of chronic postsurgical pain. Inadequate pain control can cause many complications such as respiratory, cardiovascular complications and immune dysfunction which can further decrease the patient satisfaction and increase the hospital length of stay (LOS). General anesthesia (GA) is the technique that commonly used for BCS. The downside of GA includes inadequate pain control with high incidence of postoperative nausea and vomiting (PONV). Regional anesthesia for BCS can provide better acute pain control with chronic pain prevention. It offers adequate analgesia while minimizing opioid use and its related side effects. Thoracic epidural and thoracic paravertebral blocks were the gold standard techniques in BCS. However, these techniques are generally invasive, mostly associated with sympathetic block and they are performed before induction of GA. As an alternative to these techniques, pectoral nerve block (PECS block) has been reported as a promising technique during BCS. The present study was designed to assess the efficacy of PECS block and TTP block as a supplement to general anesthesia (GA) in modified radical mastectomy (MRM).