Objective. To evaluate postoperative lymphatic compensation in the upper limb after mastectomy with axillary dissection. Subjects and methods. Twenty-three patients who underwent lymphoscintigraphy before and 60 days after surgery were enrolled from September 2006 to June 2007, in Campinas, Brazil. Protocol examination consisted in static imaging of each upper limb in semi-flexion and thoracic imaging after 10 min and 1 and 2 hr after subcutaneous injection of 1 mCi (37 MBq) of (99m)Tc dextran into the dorsum of the hand. A comparative analysis was made of hepatic uptake of the radiopharmaceutical, velocity of axillary lymph node visualization (I, visible at 10 min; II, at 1 hr; III, at 2 hr; IV, not visible) and degree (intensity) of uptake (a, marked; b, moderate; c, mild; d, absent) before and 60 days after surgery. Results. In the preoperative period, 3 (13%) patients were considered to have an optimal pattern (Ia) and 2 (9%) showed total involvement (IVd). Compared to velocity in the postoperative period, 9 (39%) patients showed no difference, 5 (22%) improved, 9 (39%) became worse, and one was considerably worse. Regarding the degree, 10 (43%) patients showed no difference, 9 (39%) became worse, and 4 (17%) improved. Regarding classification, 2 (9%) patients had an optimal lymphatic pattern (Ia) and 3 (13%) had total involvement (IVd). No patient presented decreased hepatic uptake after surgical treatment. Conclusions. The study found relevant changes in preoperative and postoperative lymphoscintigraphy, demonstrating the existence of functional differences in the lymphatic system of the upper limb. Alterations in lymphatic drainage pattern may already be perceived 60 days postoperatively, as can signs of lymphovenous anastomoses.973309315