We report a patient who was treated with a pedicled latissimus dorsi myocutaneous flap for lack of skin and loss of elbow flexion after resection of a soft tissue sarcoma in the upper limb. The patient, a 71-year-old man, had a tumor in the distal part of the left upper limb. MRI imaging showed that the tumor was located deeply, and a needle biopsy revealed a diagnosis of myxofibrosarcoma. At the time of surgery, the tumor measured 9x6x6 cm and the patient complained of local pain and slight disturbance of the range of elbow flexion. We performed wide tumor resection and sacrificed all of the biceps, part of the brachialis and brachioradialis, and the musculocutaneous nerve. After tumor resection, to cover the skin defect and allow recovery of elbow flexion, we performed functional reconstruction using a pedicled latissimus dorsi musculocutaneous flap. At the last follow-up, one year after the operation, the patient was free of local recurrence and distant metastasis. The functional result was an ISOLS score of 86.7%. It has been reported that a pedicled latissimus dorsi myocutaneous flap is useful for covering a wide range of skin defects and for restoration of elbow flexion. A pedicled latissimus dorsi myocutaneous flap has an advantage in that the patient is able to flex the elbow using the flap in the early period after reconstruction surgery. In the present case, postoperative function was as good as in other reports, and we were able to confirm the early activity of the myocutaneous flap by needle EMG.