Introduction: In the successful treatment of addicted people, in addition to drug therapy, serious attention should be paid to psychological interventions. This study aimed to determine the effectiveness of cognitive emotion regulation training (CERT) on psychological well-being and cognitive emotion regulation of addicted men in Isfahan city. Materials and Methods: This study was semi-experimental with a pre-test and post-test control group design. The population of this study consisted of all men addicted to narcotics in Isfahan referred to addiction treatment clinics in the first six months of 2019-2020 for methadone maintenance treatment. In total, 60 men were selected by the available sampling method and were randomly divided into two groups. Members of the experimental group received their groupspecific training in 8 sessions of 1. 5 hours,however, the control group received their routine training. Results: Mean and standard deviation of psychological well-being and cognitive emotion regulation of the experimental group in the pre-test were 49. 77±, 7. 59 and 78. 67±, 6. 09, respectively. Also, the mean and standard deviation of psychological well-being and cognitive emotion regulation of the control group were 49. 43±, 7. 21 and 79. 07±, 6. 00 respectively. According to the results, in the post-test, the psychological well-being score was 84. 23±, 7. 61, and the cognitive emotion regulation of the experiment was 86. 07±, 6. 10 compared to the control group (49. 27±, 6. 90 (F=357. 263) and 78. 87±, 6. 11 (F=387. 054), respectively) (p<0. 001). Conclusion: The results showed that CERT is effective in the psychological well-being and cognitive emotion regulation of addicted people. Therefore, it can be used to increase their psychological well-being and cognitive emotion regulation.