Background: seroma occurs in most patients after mastectomy. It is thought to be caused by the fact that mastectomy leaves a lot of an "empty space" under the skin where the breast tissue used to be. Aim of the work: it was to study the effect of closure of dead space by suture fixation of the mastectomy flaps to the underlying chest wall on the amount and duration of postoperative drainage and seroma formation. Patients and Methods: the current study included 40 female patients with breast carcinoma scheduled for modified radical mastectomy and they were randomized into two groups according to suture fixation of the mastectomy flaps to the underlying chest wa1l. Group I, 20 patients undergone suture fixation of the mastectomy flaps to the underlying chest wa1l raw by raw, closing every potentia1 space. Group II, 20 patients where the wound was c1osed in the conventiona1 method. Results: the flap fixation technique is a valuable procedure that significant1y decrease the incidence of seroma formation, the need for frequent visits to the physician for seroma fluid aspiration, the tota1 amount of drained fluid and also allowing for earlier remova1 of the drains as well as avoidance of complications resulting from the occurrence of seroma. Conclusion: This method appears to have much many advantages that over-exceed its disadvantage of time consumption during the operation. It should be tried on a much wider scale to prove its validity in decreasing the incidence of seroma formation and its subsequent complications.