Among 240 patients treated by radiation therapy for clinical Stage IB cancer of the cervix between 1969 and 1980, 38 patients received postoperative pelvic radiation therapy after radical hysterectomy because of positive pelvic lymph nodes and/or close surgical margins. The overall recurrence was 45% (17 of 38), and the major complication rate was 15% in minimum 5-year follow-up. In patients with positive pelvic lymph nodes, the pelvic recurrence was 13% (3 of 23). However, distant metastases alone was 26% (6 of 23), which was the most common treatment failure. In 11 patients with close surgical margins, eight patients had paracervical margins and three had vaginal margins. All five patients with paracervical margins treated with vaginal ovoid irradiation only had pelvic recurrence. No local failure occurred in the other three patients treated with whole pelvic irradiation. All patients with vaginal margin alone treated with vaginal ovoid or whole pelvic irradiation had no recurrence of cancer in the pelvis. On the basis of our data, whole pelvic irradiation with or without vaginal ovoid irradiation is necessary in those with a close paracervical margin. In patients with close vaginal margin, whole pelvic irradiation with or without vaginal ovoid irradiation is recommended. The vaginal ovoid irradiation alone should be limited to very selected cases.