Forty-five patients with Stage IB squamous cell carcinoma of the cervix uteri were treated with radiation therapy alone. The five year actuarial survival rate of the 22 patients in group 1 in whom the tumor was less than 4 centimeters in diameter was 95 per cent, which was significantly higher than the 67 per cent survival rate in the 23 patients in group 2 with bulky lesions greater than or equal to 4 centimeters in diameter, p less than 0.05. These results of radiation therapy are consistent with surgical results recently reported and indicate that patients with bulky lesions, especially those tumors greater than or equal to 4 centimeters in size, comprise a high risk subset within the Stage IB classification. A new classification is proposed in which bulky lesions are designated Stage IC, advanced overt, so that such high risk patients might be identified and more efficacious treatment regimens might be developed.