Surgery for colorectal carcinoma has supplemented the following cytokine-based procedures: (1) extracorporeal immunotherapy (EIT) with autologous rIL2-activated mononuclear cells for treatment of patients with infectious complications, and (2) extracorporeal infusion immunotherapy with native cytokines (perfusate of xenospleen) to prevent postoperative infectious complications. EIT was followed by an effective correction of T-cell immunodeficiency and rehabilitation of monocytic function; rapid decrease in symptoms of endotoxicity; improved response to conventional therapy, and, as a result, a fall in mortality rates (from 38.9 to 11.7%). Immunotherapy with native cytokines brought about a significant decrease in postoperative complication incidence (36.4-15.8%), the average length of stay in hospital falling by 6.8 days. Immunological correction with cytokines was instrumental in raising the efficacy of surgical treatment of colorectal tumors.