Malignant mesothelioma of the peritoneum is a rare tumour for which the therapeutic approach has not yet been standardized. The efficacy of the current regimes is limited. Effective locoregional therapy is crucial, since this tumour is most often confined to the peritoneal cavity at the time of the initial diagnosis and remains there for much of its clinical course. If and when haematogenous metastases occur, they rarely contribute to the death of the patient, which is often caused by the overgrowth of the primary tumour and its local complications. A case of diffuse malignant peritoneal mesothelioma treated by cytoreductive surgery and continuous hyperthermic peritoneal perfusion with cisplatin is reported. The patient received systemic combination chemotherapy postoperatively. She is in good condition and free of disease 28 months after her treatment. Continuous hyperthermic peritoneal perfusion chemotherapy has recently been used in patients with secondary peritoneal carcinomatosis from digestive and gynecological malignancies with promising results. It is also possible that the same treatment alone or in combination with systemic chemotherapy may be effective in the treatment of primary peritoneal malignancies, as in the case of diffuse peritoneal mesothelioma.