Malignant mesothelioma of the peritoneum is a rare tumour for which thetherapeutic approach has not yet been standardized. The efficacy of thecurrent regimes is limited. Effective locoregional therapy is crucial, sincethis tumour is most often confined to the peritoneal cavity at the time of theinitial diagnosis and remains there for much of its clinical course. If andwhen haematogenous metastases occur, they rarely contribute to the death ofthe patient, which is often caused by the overgrowth of the primary tumour andits local complications. A case of diffuse malignant peritoneal mesotheliomatreated by cytoreductive surgery and continuous hyperthermic peritonealperfusion with cisplatin is reported. The patient received systemiccombination chemotherapy postoperatively. She is in good condition and freeof disease 28 months after her treatment. Continuous hyperthermic peritonealperfusion chemotherapy has recently been used in patients with secondaryperitoneal carcinomatosis from digestive and gynecological malignancies withpromising results. It is also possible that the same treatment alone or incombination with systemic chemotherapy may be effective in the treatment ofprimary peritoneal malignancies, as in the case of diffuse peritonealmesothelioma.