We wished to determine whether the number of central nervous system (CNS) white matter lesions on magnetic resonance imaging (MRI) is increased in patients with nonarteritic ischemic optic neuropathy (NAION). T2-Weighted axial images of the brain in 13 patients with acute NAION and 16 age-matched controls were used to tabulate the number of subcortical and periventricular white matter lesions. Groups were compared by t test for means, the Wilcoxon-Mann-Whitney rank-sum test, and chi-square test for proportions with at least one lesion. The mean number of CNS white matter ischemic lesions in the NAION group was 4.0 (range 0-20) as compared to 1.4 (range 0-7) in the control group. The difference in these samples suggested a significant increase in NAION (p = 0.069, rank-sum test). The proportions of patients with at least one lesion were not significantly different (53.8% NAION vs. 56.3% controls). The data suggest an increased number of CNS white matter lesions in patients with NAION.