Abstract: The main aim of current study was to survey on the effectiveness of transactional analysis group training on the prisoners’ aggression reduction. The 24 voulentry prisoners ( Experimental Group = 12, Control Group = 12) were selected using available sampling method and has been observed objectively as well as been scored using the Spielberge Aggressive questionnare. The experimental group was trained under the transactional analysis training for 12 sessions. The results indicated a significant effect of the transactional analysis training on the on the prisoners aggression decreasing.