Lumbosacral plexus lesions developed in two women 8 and 14 years, respectively, after operation and irradiation for carcinoma of the uterus. In both patients, a left femoral nerve lesion was the presenting sign. The irradiation dose was about 5,000 rad on both sides in patient 1 and 8,400 rad on the affected side in patient 2. Both patients had low-frequency periodic discharges in the EMG.