Malignant fibrous histiocytoma (MFH) and dermatofibrosarcoma protuberans (DFSP) grow in an infiltrative fashion and have a high risk of local recurrence. Major loss of function is likely to occur in surgical resection of these tumors in the forearm because of the infiltrative nature of the tumor and the anatomical complexity of the forearm. We report three cases of these conditions (2 MFH and 1 DFSP) those were treated surgically with a wide marginal resection and reconstruction using an anterolateral thigh flap. Six or more muscles in all cases and the distal ulna in two cases were resected with the tumor. Functional reconstruction was performed by muscle transfer in 2 cases and a fascia lata graft in 1 case. Skin and soft-tissue defects were covered with an anterolateral thigh flap in all cases. Postoperative complications were partial necrosis of the flap in one case and dislocation of the radial head in one patient whose distal half of the ulna was resected. One patient developed lymph node metastasis and underwent surgery. At the last follow-up, all patients were free of local recurrence. Functional results in these patients were an ISOLS score of 70-80% and a DASH score of 30-35 points. An adequately wide procedure and reconstruction with an anterolateral thigh flap are able to achieve good local control and limb salvage with acceptable limb function.