The McCarron-Dial System (MDS) has successfully predicted vocational and independent living outcomes with neuropsychologically disabled individuals receiving rehabilitation services. In addition, preliminary validation studies suggest that the abbreviated MDS is useful for clinical neuropsychological diagnosis. The present study represents part of an ongoing research project aimed at validating the expanded version of the MDS for diagnosis of neuropsychological dysfunction. Specifically, it was hypothesized that the expanded MDS would be able to accurately discriminate between brain-damaged and non-brain-damaged individuals. Accurate diagnosis facilitates rehabilitation efforts for individuals with neuropsychological disabilities and the data profile provided by the expanded version of the MDS can consequently form the basis from which more complete individual treatment and rehabilitation plans can be conceptualized.