From August 1995 to June 1999, 140 free anterolateral thigh (ALT) flaps were transferred to reconstruct a variety of soft-tissue defects. The size of ALT flap ranged from 10 to 33 cm in length and 4 to 14 cm in width. Based on the anatomic variations of the perforators, the blood supply to the skin island came from the septocutaneous perforators only in 19 patients (13.6%), arising from the descending or transverse branch of the lateral circumflex femoral artery (LCFA), or originating directly from LCFA. The other flaps were supplied by musculocutaneous perforators that were elevated as a true perforator flap via intramuscular dissection (N = 34, 24.3%), or used a cuff of vastus lateralis muscle for added bulk (N = 87, 62.1%). The overall success rate was 92% (129 of 140). After a 2-year follow-up, all flaps have healed uneventfully and donor thigh morbidity is minimal. Anatomic variations must be considered if the ALT flap is to be used safely and reliably.