A number of research studies have proposed various methods for using the MMPI to identify brain dysfunction. This previous research has taken one of three major approaches. The present study compared the major approaches in a population consisting of 30 schizophrenic, 30 brain-damaged and 30 hospitalized normal patients. The results indicated that the most effective diagnosis device was the use of the Sc scale alone or in conjunction with the remaining clinical scales and the F scale. None of the organic scales or keys were able to match the performance of the Sc scale alone. The poor results obtained bring into question the use of these scales in any other setting without an extensive research validation. An alternate method that might be used to employ the MMPI in the diagnosis of brain dysfunction was suggested.