The authors studied the ability of the Kincannon Mini-Mult validity scales to detect invalid standard MMPI protocols of adult male prisoners. The original MMPI records of 1407 Ss were rescored by use of Kincannon's items for the L, F, and K Scales. Analysis consisted of examining the frequency with which the Mini-Mult would detect an invalid protocol when at least one of the original MMPI validity scales also was elevated and invalid. Results indicate that the Mini-Mult failed to detect nearly 75% of the profiles that were invalid due to an elevated F scale on the parent MMPI. Similarly, over 50% of the profiles invalid due to elevated L and/or K scales were not detected by the Mini-Mult. Despite the appealing brevity of this 71-item short form of the MMPI, caution is advised with regard to its use in penal settings.