Malignant peritoneal mesothelioma is an aggressive neoplasm that rapidly spreads within the confines of the abdominal cavity to involve most accessible peritoneal and omental surfaces. Current treatments are unsatisfactory, and new approaches are needed. We have noted prolonged survival in selected patients after intensive multimodality treatment. Our current experimental regimen includes initial laparotomy with omentectomy, resection of peritoneal implants, and placement of bilateral peritoneal Port-a-Caths (Sims Deltec, Inc., St. Paul, MN); repeated courses of intraperitoneal chemotherapy with doxorubicin, cisplatin, and interferon gamma; second-look laparotomy and intraoperative hyperthermic perfusion with mitomycin and cisplatin; and whole abdominal radiation. Patients with peritoneal mesothelioma who are not candidates for this approach can sometimes be palliated with systemic (intravenous) chemotherapy using doxorubicin or mitomycin, alone or in combination with cisplatin or carboplatin. Newer agents such as gemcitabine and multitargeted antifolate (pemetrexed disodium, LY231514) show promise of greater effectiveness.