Studied the effects of a 3-phase moral education program with 27 adult male inmates over a 7-mo period. Ss making up 5 groups from a medium- and minimum-security institution were randomly assigned and matched for stage of moral development, age, ethnic group, prior record, and governing offense. The overall mean score of 2 experimental groups from the minimum-security institution and 1 experimental group from the medium-security institution were significantly higher than the overall control group mean score for ego development and moral judgment. In addition, there was a significantly positive relationship between ego and moral development. (PsycINFO Database Record (c) 2019 APA, all rights reserved)