<b> Introduction:</b> Post-operative seroma formation is one of the most common complications following modified radical mastectomy (MRM). Quilting is a technique where the mastectomy flaps are sutured to the underlying chest wall muscles with sutures, obliterating the dead space. The authors hypothesised that post-mastectomy dead space obliteration by intermittent mastectomy flap fixation leads to decreased drain output and seroma formation. </br></br> <b> Material and methods: </b> A double-blinded randomised control trial with two arms was conducted from November 2019 to March 2021 in our institute located in India. Patients with non metastatic breast carcinoma planned for MRM were randomly categorised into two groups of 35 patients each. In the test group, each flap was fixed to the underlying muscle using four intermittent 3-0 polyglactin sutures, which was followed by skin closure, and only skin closure was done in the control group. </br></br> <b>Results:</b> The test and control groups did not differ significantly with respect to demographic and tumour characteristics. The average drain output of the test group (155.43 ml) was significantly less than of the control group (206.29 ml). The overall incidence of seroma formation is lower in the test group (5.7%) when compared to the control group (28.6%). The duration of hospital stay in the test group (4.63 days) was significantly shorter when compared to the control group (6.66 days). There was no significant increase in the overall operating time or complications like surgical site infection or skin dimpling due to flap fixation. </br></br> <b>Conclusions:</b> Fixation of MRM flaps is associated with better post-operative outcomes related to drain output and seroma formation without a significant increase in other morbidities or usage of resources.