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