Introduction: Surgical management of breast cancer includes breast conservative surgery & mastectomy. Studies showed that patients receiving post mastectomy radiotherapy (PMRT) after modified radical mastectomy (MRM) has lower 10 years rate of local recurrence & better survival rate than those who didn’t receive PMRT according to the Danish breast cancer cooperative group 82b, 82c (1, 2) & another Canadian research also supported that PMRT reduces rate of local & systemic relapse & reduces mortality from breast cancer (3). Patients undergoing MRM face a strong psychological trauma as they are set to lose an important sexual characteristic & also facing the deformity of their body figure causing more conflict in their life, so emerged the idea of immediate breast reconstruction after MRM, as these patients received both surgeries together rather than the traditional method of delayed reconstruction which offer not only cosmetic but also psychological advantages. Immediate flap reconstruction whether it will interfere with long term survival or not must be taken into consideration. However there was no study concerned with effect of immediate TRAM on long term survival rate with PMRT, so keeping the patient best interest in mind, emerged the idea of the study is to identify the influence of immediate breast reconstruction on survival rate in patients receiving PMRT. Aim of the work: To identify the effect of immediate transverse rectus abdominismyocutaneous flap reconstruction on long term outcome of post mastectomy radiotherapy. Methods and methods: In this prospective study 74 patients were managed at Ain shams university hospital from February 2014 to February 2017 from whom the following data were collected: age at diagnosis, adjuvant CT & hormonal treatment, information regarding primary surgery, local recurrence & distant metastasis, hormonal receptor status, histological diagnosis & staging, all stages were determined according to American joint committee on cancer (AJCC) staging system 6th edition. Pre treatment work up including history, physical examination, CBC, liver function tests, chest radiography, abdominal ultrasound, serum carcinoembryonic antigen, CA-153 test & technetium99 bone scintigraphy in addition to counseling as regards breast reconstruction. Results: Among 74 patients ,36 had immediate TRAM flap reconstruction &38 didn’t had immediate TRAM flap reconstruction ,follow up for 3 years , 3year overall survival rate were 61% for TRAM flap group58% for the non - flap group.3year disease free were 58% for the TRAM flap group 61% for the non- flap group. Conclusion: According to our statistical data there is no significant difference between immediate TRAM flap reconstruction &no reconstruction in terms of local recurrence, distant metastasis, disease free & overall survival rate in patient receiving PMRT.