We studied the effectiveness of a newly-developed cognitive-behavioral intervention in 15 patients with marked cognitive impairment and behavior disorder. The design was a single-blind test of a neuropsychological intervention, with pre- and post-treatment assessments of personality and social behavior. MS patients underwent neurological examination and neuropsychological testing at baseline. The patients were then randomly assigned to neuropsychological counseling or standard, non-specific supportive psychotherapy. The active 12-week treatment emphasized enhancement of insight through education, social skills training, and behavior modification. All patients were re-examined within 2 weeks of the termination of treatment. Neuropsychological technicians were blind to treatment condition. Both groups showed evidence of cognitive impairment and personality/behavior disorder prior to treatment and were well matched on demographic, disability, and cognitive measures. Patients who underwent neuropsychological counseling showed significant positive response on measures of social behavior (e.g. excessive ego-centric speech) compared to those who underwent standard counseling. We conclude that these data support the use of non-pharmacological, neuropsychological counseling in patients with acquired, MS-associated behavior disorder.