The juvenile correction and rehabilitation center is a place for reforming and rehabilitating juvenile adolescents. The aim of this study was to determine the effect of mindfulness-based training on aggression and empathy of adolescents at the juvenile correction and rehabilitation center in Tehran. The research was a quasi-experimental design with pretest-posttest and the control group. The statistical population of the study was all of the adolescents in the juvenile correction and rehabilitation center in Tehran. In this research sampling method was convenience sampling method (availability sampling). In this regard, two groups of 16 were selected for each experimental and control. At the implementation stage, 4 participants from the experimental group and 4 from the control group were excluded. Finally, sample of 24 adolescents was randomly assigned into experimental and control groups and responded to the Batson Empathy Questionnaire and Buss and Warren’s aggression questionnaire. The experimental group received a 90-minute session for 8 sessions and a weekly 90-minute session, and no training was taken in the control group. Multivariate covariance and variance analysis was used for data analysis. The results showed that there is a significant difference between the two groups of experimental and control after the implementation of mindfulness-based training in terms of empathy and aggression components. Mindfulness-based therapy led to empathy promotion and reduction of aggression components in adolescents at the juvenile correction and rehabilitation center.