Following the resection of its primary lesion, continuous hyperthermic peritoneal perfusion (CHPP) with anticancer drug (mitomycin C, cisplatin) containing warmed physiological saline was performed on gastric cancer having peritoneal dissemination, and the effect of CHPP was examined by second look operation (SLO). The subjects were 41 cases of gastric cancer with peritoneal dissemination but without hepatic metastasis, which we have experienced in the past 7 years. The prognosis of these CHPP-treated cases was such that 50% survival period, 3 year survival rate and 5 year survival rate were 398 days, 28.5 and 12%, respectively. Comparison of the effects of CHPP by SLO revealed remarkable diminution of the peritoneal dissemination in 7 (44%) of 16 cases and disappearance of the ascites with a single course of CHPP in 7 of ascitic cases. Long-term survival (greater than 3 years) was noted in 4 of the CHPP-treated cases. Side effects were renal insufficiency, leukopenia and small intestinal perforation in 2(5), 2(5) and 1 cases (2%), respectively. The above results suggested the effectiveness of CHPP for the treatment of gastric cancer having peritoneal dissemination.