This review focuses on the underlying rationale for the use of cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CS+HIPEC) in the treatment of patients with primary gastrointestinal tumors with metastatic peritoneal disease. It examines the advantages of CS+HIPEC in peritoneal cancers and explores the controversies surrounding this treatment. For low-grade cancers, such as pseudomyxoma peritonei, CS+HIPEC is standard of care. However, for more aggressive tumors, such as gastric cancers, the results with this approach are not as encouraging and patient selection is very important. Generally, the cost of HIPEC is not prohibitive and increases the cost of surgery by only a small percentage. Overall, the consensus is that HIPEC is probably beneficial for less aggressive cancers. We believe that CS+HIPEC should be standard of care for appendiceal and colorectal cancers with peritoneal disease. For other cancers, such as gastric, pancreatic, or small bowel cancers, further study is warranted.