Abnormalities on CT or MRI and neuropsychological performance in patients with low-grade glioma, with (n = 23) or without (n = 16) prior cerebral radiotherapy, were evaluated. Cerebral atrophy was observed in 14 of 23 patients (61%) treated with prior radiotherapy, and in 1 of 16 patients (6%) without prior radiotherapy. White matter abnormalities were observed in six patients, all of whom were treated with prior radiotherapy. These radiologic cerebral abnormalities correlated with cognitive performance.