The lateral arm flap was reported first by Song et al. in 1982, and Katsaros and colleagues described an anatomic study and clinical cases in 1984. This flap is thin, has relatively constant vascular anatomy, and provides relatively acceptable scar at the donor site. Despite its many advantages its wide application has been limited by its short vascular pedicle with small diameter of lumen, and its small skin paddle. We studied its anatomical structure to get longer length of vascular pedicle, wide diameter and thinner part of flap beyond the lateral condyle through 6 fresh cadaver dissection and dye injection study. We experienced 21 cases of lateral arm free flaps and 26 cases of forearm free flaps from May, 1992 to January, 1996. We compared its usefulness with forearm free flaps in the aspects of donor morbidity, operative factors, quality of flap, and versatility. In conclusion, lateral arm flap can replace the role of forearm flap in most cases so that patient's donor morbidity can be reduced especially in the women.