Peritoneal dissemination is the most frequent cause of death from gastric cancer, accounting for death in 20% to 40% of patients. Preoperative intraperitoneal chemotherapy, peritonectomy, intraoperative chemohyperthermic perfusion, and early postoperative intraperitoneal chemotherapy are treatment modalities specifically designed to eliminate peritoneal dissemination and progression. Preoperative intraperitoneal chemotherapy is for containment of peritoneal free cancer cells, and also may facilitate complete eradication of visible peritoneal dissemination by peritonectomy. Further, complete cytoreduction can be achieved more often when peritonectomy is included in the surgical treatment of gastric cancer with peritoneal dissemination. Phase III data shows prolonged survival attributed to complete cytoreduction. Aggressive cytoreduction of peritoneal dissemination by peritonectomy can reduce residual tumor burden to micrometastases on the peritoneal surface that can be treated by intraoperative intraperitoneal chemotherapy and early postoperative intraperitoneal chemotherapy. Among all these modalities, surgical cytoreduction is probably the most important for survival benefit. If the surgical cytoreduction is visibly incomplete, prolonged survival cannot be expected, despite subsequent treatment. The surgeon's goal is to reduce the cancer cell burden to a microscopic level. Continued refinement of phase II studies is needed for maximal benefit and to standardize the technical and chemotherapeutic options of each modality.