Both multiple sclerosis (MS) and neuro-Behcet's disease (NBD) can cause a cognitive dysfunction mainly involving the executive functions. We conducted this study to clarify the probable differential cognitive/behavioral profiles of MS and NBD. Twenty consecutive cases with parenchymal NBD (13 male, seven female), and 20 cases with MS (five male, 15 female) were evaluated. Both groups had a thorough neurological examination; an evaluation for Expanded Disability Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC), and Beck's Depression Scale; and a detailed neuropsychological evaluation masked to the diagnosis. Among the two groups, male/female ratio differed significantly while other demographic and clinical features were not different. In California Verbal Learning Test, both short-and long-term delayed recall and cued recognition were worse in neuro-Behcet's cases. They had impaired semantic clustering and increased false positives. Stroop Test was also more impaired in neuro-Behcet's cases. They needed significantly more trials to complete the first category of the Wisconsin Card Sorting Test and had a poorer total Frontal Behavioral Inventory Score. Our results suggest that neuro-Behcet's patients have a more severe "frontal"-executive dysfunction than MS patients.