Background: To investigate the effects of double radiofrequency hyperthermia on Th1/Th2 cells in esophagealcancer patients treated with radiotherapy. Materials and Methods: 22 patients with esophageal cancer weredivided into a radiotherapy group (10 cases) and a combined group (double radiofrequency hyperthermiacombined with radiotherapy group, 12 cases). Both groups received conventional radiotherapy using a cobalt-60therapy apparatus (TD60-66Gy/30-33F). Patients in the combined group also underwent double radiofrequencyhyperthermia (2F/W, 8-10F). Before and after treatment, Th1, Th2, Tc1 and Tc2 cells in peripheral bloodwere determined with flow cytometry. Results: In the radiotherapy group, Th1 cell contents before and afterradiotherapy were 17.5±5.26% and 9.69±4.86%, respectively, with a significant difference (p<0.01). The Th1/Th2ratio was significantly decreased from 28.2±14.3 to 16.5±10.4 (p<0.01). In the combined group, Th1 cell contentbefore radiotherapy was 15.9±8.18%, and it increased to 18.6±8.84 after radiotherapy (p>0.05), the Th1/Th2ratio decreasing from 38.4±36.3 to 28.1±24.0 (p>0.05). Changes in Th2, Tc1 and Tc2 cell levels were not significantin the two groups before and after therapy (p>0.05). Conclusions: Double radiofrequency hyperthermia canpromote the conversion from Th2 to Th1 cells, and regulate the balance of Th1/Th2 cells.