The object of this study is to develop and to evaluate an education program for prison inmates based on voluntary participation, including the method of role lettering. Twelve prison inmates participated in this program from January to April 2015 in the first term period and thirteen from May to August 2015 in the second term composed of twelve meetings with each session lasting for four hours (including the tasks of the specific lecture) at Z prison in Korea. The main method of this education program is “role lettering” added to group work and audio-visual stimulation. In order to prove the effectiveness of this program, the pre-test- /post-test-design was utilized to evaluate the inmates’ self-esteem, ability to express empathy, anger, and impulsivity. The results of the analysis are as follows: Based on statistical evidence found by comparing the data from pre- and post-intervention, in three out of the four mentioned scales (self-esteem, empathy, and impulsivity), the conclusion that the education program was efficient can be made. On the anger scale, however, the significant effectiveness of education can be recognized during the first term period, while there was no effect in the second. The findings, moreover, suggest that the education program can generate different results according to the individual features of the educated group of inmates such as their age, the term of imprisonment, and the crime they have committed.