Aim: To assess efficacy of shorter fractionated Radiotherapy in post mastectomy cancer breast patients Methods:  Inclusion Critaria– Histopathologically proven cases with Infiltrating Duct Carcinoma (IDC), Post mastectomy cases, No prior treatment (Except surgery and chemotherapy with CAF)  Node Positive Cases,T3 & T4 Tumours, Positive surgical margins Exclusion Critaria: Metastatic-disseminated disease, Female less than 18 years and more than 70 years, Severe medical illness like heart disease, COPD, Neurological disorder. Between July 2012 to July 2014, 172 patients were included and divided into three groups, Control Group and two Study Groups. 3D-CRT Radiotherapy was given in Control Group in a dose of 50 Gy in 25# for 5 weeks.  One study group  received radiotherapy of 4000 cGy in 15# for 3 weeks and another study group received 4250 cGy in 16# for 3 ½ weeks. Linear Accelerator was used for the radiation treatment. Ipsilateral supraclavicular fossa (SCF) irradiation was done in patients who had more than 3 axillary nodes positive, patients who had positive supraclavicular nodes at presentation and those with inadequate axillary nodal dissection. Results: At 2 years, the incidence of chest wall stiffness in the study group 1 was 44.64%, in study group 2 it was 47.36% and 47.45% patients were in control group. The incidence of arm edema was 16.07% in the study group 1, 15.78% in study group 2 and 18.64% patients in control group. Local recurrence-free survival was 96.42% in the study group 1, 98.24% in study group 2 and 98.3% in the control group. Not a single patient had developed radiation pneumonitis. Conclusion: Shorter fractionation schedule is very much effective in preventing recurrent breast cancer and it provides a high level of patient satisfaction as well as reduced money and overall treatment time. Its shorter duration offers the added advantage of a more efficient use of resources and greater patient convenience.