The purpose of this study was to investigate the diagnostic validity of a neuropsychologically-based vocational evaluation battery, the McCarron-Dial System (MDS), in differentiating between brain-damaged and non-brain-damaged rehabilitation clients. Multiple discriminant analysis results indicate that 89% of the subjects were correctly classified. The results tentatively support the validity of the MDS for neurobehavioral diagnosis. However, additional emotional and behavioral information may be needed to increase classification accuracy and to determine more specific diagnosis. Because of its long tradition in vocational rehabilitation and established strengths in predicting vocational and community adjustment outcomes, the MDS may be potentially useful for both vocational and clinical neuropsychological assessment.