The research looked at whether original MMPI-1 rules developed to classify offender profiles could be used with the revised MMPI-2. A preliminary study using estimated MMPI-2 profiles on 100 male offenders who had been previously tested and classified according to MMPI-1 indicated that only 51.6 could be classified in the same categories when the original classification rules were applied to their estimated MMPI-2 profiles. In the main investigation, two datasets were used. The first phase data set consisted of MMPI-1's from 1,163 youthful male offenders who had been tested and classified in the course of the initial derivation and validation of the MMPI-based system during the early 1970's. Their MMPI-1 responses were rescored using MMPI-2 procedures and norms. Estimated MMPI- 2's were then classified using the original rules developed for MMPI-1 and the resulting classifications were compared. Of 1,075 subjects who could be classified on both measures, 644 or 59.9 percent received identical classifications. The second-phase dataset consisted of MMPI-2's obtained from 422 adult male prisoners. Researchers scored the MMPI-2's on these subjects and, using special algorithms, estimated what their MMPI-1 profiles would have been. About 65 percent of the subjects received the same classifications. A test sample of 200 consecutive cases was drawn from the first- phase subject pool and classified on the basis of new rules for MMPI-2 that would enable the classification of MMPI-2 profiles to better approximate classifications that probably would have been obtained had MMPI-1 been administered. The new rules resulted in identical classifications for 84 percent of the cases. It is recommended that the new rules, included in the report, be used instead of the original rules when classifying the MMPI-2's of male offenders. Appendixes provide further information on offender classification. References, tables, and figures