Aims: The purpose of this study was to evaluate the effectiveness of Acceptance and Commitment-Based Therapy (ACBT) on anger, anxiety and hostility in heart surgery patients. Materials and Methods: The present study was quasi-experimental (pre-test, post-test) with experimental and control groups. A follow-up test was conducted two months after the post-test. The statistical population consisted of all patients referring to Vali-e-Asr Hospital in Ghaemshahr during January-February 2017 having a heart surgery and medical record (N = 112). According to the research method, which is a quasi-experimental design, 30 persons were selected through "available sampling" and randomly were assigned to the intervention and control group (15 participants in each group) by inclusion and exclusion criteria. The tools used in this study include Spielberger's Anger Scale (1988), Redford - Williams Hostility Inventory (RWHI) (1981), Beck anxiety (1988), which were provided to the groups for pre-test. After pretest, treatment for the heart surgery patients was performed in the intervention group by a trained psychiatrist doctor student based on ACBT protocol, and the control group did not receive any treatment. We collected data directly after the intervention (first posttest) and 2 months later (second posttest) in both groups. For the research hypotheses test, covariance analysis and SPSS-21 software were used. Results: The results of covariance analysis indicated that ACBT had a significant effect on all three psychological variables studied in the post-test. Conclusion: ACBT has decreased the anger, anxiety and hostility of heart surgery patients in the intervention group.