Malignant soft-tissue tumors of the abdominal wall consist of desmoid tumors and nondesmoid soft-tissue sarcomas. These neoplasms tend to invade adjacent musculoaponeurotic and bony structures. Transperitoneal organ invasion can also occur with devastating sequelae, especially after an incomplete excision. Extirpation with the full-thickness of the abdominal wall is required except for small, superficial lesions. A wide-margin resection, including any adherent viscus, segments of adjacent ribs, and iliac or pubic crest, offers the best assurance of local control. Adjunctive radiotherapy can be given when the margin of resection is unavoidably limited, but an effective radiation dose can be difficult to administer, due to the sensitivity of underlying intestines. Metastases develop frequently with high-grade sarcomas; adjuvant chemotherapy may be tried in these patients, but its value remains unproven.