Background: Vacuum suction drainage is an obligatory practice for long past following mastectomy for breast cancer. But recent studies are showing that the pressure of the vacuum suction drain is of value in determining the volume of seroma formation and thereby the drain indwelling time, duration of hospital stays and patient morbidity. Half vacuum suction may be of greater value in this regard comparing full vacuum suction drainage. Objectives were to assess and compare the clinical outcome of half versus full vacuum suction drainage following modified radical mastectomy for breast cancer. Methods: Forty patients of histologically proven breast cancer had been chosen purposively and systematically randomized in two equal groups. Group A with half vacuum suction (device was squeezed up to half of its vertical length) and group B with full vacuum suction (device was squeezed to its maximum). The outcome measured were postoperative drainage, drain indwelling time and post-surgery length of hospital stay. Results: Patients having half vacuum suction had a significantly reduced mean total drainage volume (364.25±128.52 ml versus 822.00±251.30 ml), drain indwelling time (5.50±1.32 days versus 9.05±1.90 days) and post-surgery hospital stay (7.15±2.58 days versus 10.25±2.55 days) in comparison to the full vacuum suction group. No significant difference found in regards to postoperative pain and other wound related complications. Conclusions: We concluded that half vacuum suction drain ensures a lower drain collection and were removed earlier and hence reduced the hospital stay significantly than full vacuum suction drains.