PURPOSE: The latissimus dorsi flap and the serratus anterior flap have been used as combined flaps to reconstruct extensive defects. Because these two muscles are usually supplied by the subscapular- thoracodorsal vessels, the two flaps can be based on vascular pedicle that is long and anatomically reliable. In this case, we reported that serratus anterior possessed an anomalous arterial supply totally independent from the subscapular pedicle while raising combined latissimus dorsi and serratus anterior flap. METHODS: A 35-year-old male with extensive soft tissue defect in the left perineum and thigh visited. Muscle defects of the medial thigh were observed, and femoral nerve and vessels were exposed. Combined latissimus dorsi and serratus anterior free flap was raised to reconstruct defect. On raising flaps, artery supplying the serratus anterior muscle originated from the axillary artery directly, was lying on the undersurface of the serratus anterior muscle. RESULTS: Because two flap pedicles had no communication and latissimus dorsi muscle was large enough to cover soft tissue defect, we transferred only latissimus dorsi free flap with 1:3 meshed skin graft. Patient had limb salvage and satisfactory functional outcome. CONCLUSION: There are many variations of arterial pedicles of flaps. However, most of these variations remain within known anatomical consistence, thus is an indicator in planning the dissection of the vessels. According to documents, arterial pedicle to the serratus muscle not originated from the thoracodorsal artery is rarely reported, and in most of these cases, the arteries are originated from the subscapular artery. Thus pedicle directly originated from the axillary artery to serratus muscle is a very rare variation in its vascular anatomy.