The need for a thin flap has increased for contour or coverage of the shallow defects caused by trauma, tumor ablative surgery, or defects created after the release of contractures. The authors describe their experience with the use of an extremely thin anterolateral thigh free flap for covering such defects in a series of 12 patients. Extreme thinning of the flap (4-5 mm) was achieved by removal of deep fascia and subcutaneous fat except for a 3- to 4-cm area around the entry of the perforator into the flap. Subdermal fat and immediate underlying superficial veins should be preserved during the thinning procedure for venous drainage of the flap. Their clinical experiences with 12 patients indicate that an extremely thin, long flap can survive on a single perforator.