A total of 151 patients with Stage I carcinoma of the uterine cervix received treatment with intracavitary irradiation alone between 1948 and 1971. All patients had a minimum follow-up of five years. There were no local failures. No patient with microinvasive carcinoma (Stage IA) had a regional failure. A maximum of 4% (4/93) of patients with invasive cancer less than 1 cm in diameter (Stage IB-Small Volume) had regional failures. The five year determinate survival rates for patients with Stage IA and IB (Small Volume) lesions were 100% and 96% respectively. The incidence of severe complications was low, with a fistula developing in only one patient. Treatment with intracavitary radium alone is sufficient for patients with invasive cancer less than 1 cm in diameter who have adequate anatomy that allows effective irradiation of the primary lesion and paracervical lymphatics.