Peritonectomy was done for 125 patients with peritoneal carcinomatosis (PC): 19-pseudomyxomaperitonei (PMP), 15-appendiceal carcinoma (AC), 20-colorectal cancer, 67-gastric cancer, 2-small bowel cancer and 2-peritoneal mesothelioma. Cytoreduction by the standard techniques was done in 130 patients with PC. Complete cytoreduction (CC-0) was achieved in 85 of 125 (68%) patients, who have undergone peritonectomy, but was performed only in 28 of 130 (21%) by the standard surgical techniques. CC-0 could be done to patients with peritoneal cancer indices (PCI) of less than 14. A Cox model showed that significant prognostic factors are CC-0, and the patients were younger than 66 years old. Accordingly, peritonectomy increased the incidence of CC-0, and may have improved the prognosis of patients with PC. Peritonectomy is recommended for patients with PMP, AC and colorectal cancer. In gastric cancer, it is indicated for patients with PCI less than 14.