The records of 146 consecutive patients with mastectomy operations over a three year period were reviewed. Of these, ninety-three (63.6 per cent) had one or more complications secondary to surgery. There were 175 complications, of which complications, of which 107 (73.2 per cent) were wound-related. Seroma formation occurred most frequently but was of minor consequence. The incidence of flap necrosis was 19.1 per cent, with cellulitis or suppurative infection appearing in thirteen patients. Immediate postoperative edema of the arm was fairly rare (2.7 per cent) and appeared related to delayed wound healing. Postoperative complications after total, modified radical, and radical mastectomy present problems unique from those seen after other major surgery, in that local complications predominate. The very nature of the procedure, with the creation of large thin skin flaps, extensive axillary dissection, and an open wound for a prolonged period of time, predisposes to wound morbidity.