The authors report the results of clinical elaboration and testing of the technic of intraesophageal intratumor sarcolysin iontophoresis associated with radiotherapy in 40 inoperable patients with cancer of the thoracic esophagus. A total focal dose of irradiation was on the average 1/3 less compared with the routine one. Iontophoresis was performed by a specially designed electrode with 5-10 mA during 60 minutes. The iontophoresis procedure was followed by irradiation. The immediate good results of the treatment were twice as frequent as in control groups. The treatment proceeded with less pronounced radiation response. An average survival of patients while using chemical drugs intophoresis proved to be equal to control data that is likely to be due to the far-advanced stage of the disease in most patients. An average survival in patients with less tumor proliferation was found to be longer than in analogous control series.