During recent years ablative technologies have become very popular in tumor treatment. They are used in treatment for inoperable primary and metastatic tumors of the liver and the lung and also localized renal tumors of small sizes. The most studies on thermoablation in oncology are focused on the evaluation of tissue destruction and optimization of physical mechanisms, while potential mechanisms of immune response in thermoablation are still far from understanding. This study shows that with thermoablation of tumor within one month after the procedure the formation of a protective immune response is observed by increasing the content of activated T-helpers and cytotoxic T-lymphocytes.