Initial attempts to obliterate dead space and minimize fluid accumulation in patients after mastectomy using closed suction drainage, used insertion of a single axillary drain. Today, surgeons often insert two drains in the postoperative wound, one in the axilla and the other beneath the pectoral flaps. The current study was done to determine whether or not there is an advantage in using two drains rather than a single axillary drain after mastectomy. A randomized, clinical trial was conducted with 84 women undergoing modified radical mastectomy. Thirty-seven patients had one axillary drain and 47 had two drains placed postoperatively, one in the axilla and the other beneath the pectoral flaps. Follow-up results were obtained four weeks postoperatively for complication data, including seroma and hematoma formation, flap necrosis and infection. The average total drainage was 870.4 milliliters per patient in the group with one drain and 997.4 milliliters per patient in the group with two drains (p value not significant). The overall complication rate in the group with one drain was 35.0 percent compared with a rate of 31.9 percent for all complications observed in the group with two drains. These differences did not reach statistical significance. Comparing the frequency of each complication in the two groups again showed no significant difference. However, the data suggest a trend toward an increased incidence of flap necrosis in the group with two drains that used a drain beneath the pectoral flaps. Use of a single axillary drain after modified radical mastectomy seems to result in no increase in postoperative complications, is less costly and may assist in reducing the incidence of flap necrosis.