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Multiple sclerosis (MS) patients frequently experience impaired verbal working memory (VWM). Functional magnetic resonance imaging (fMRI) may help identify neural mechanisms underlying these deficits. Neuroimaging studies of healthy adults have characterized responses associated with increased VWM demands during the n‐Back task, suggesting that this experimental paradigm could help identify neural correlates of VWM deficits among MS patients. Fifteen MS patients and 15 matched control participants completed the n‐Back during whole‐brain fMRI. Mean signal during adjacent 0‐Back blocks was subtracted, on a voxel‐wise basis, from mean signal observed during n‐Back blocks. Resulting difference scores for 1‐, 2‐, and 3‐Back were compared across groups and difficulty levels. Signal intensity was positively related to difficulty level in anterior regions, including premotor, supplementary motor …