Hostility is a trait dimension that consists of a tendency to (I) behave aggressively, (II) experience angry affect and (III) hold cynical cognitions (e.g., hostile beliefs), that can be considered a transdiagnostic phenomenon in mental disorders. While Cognitive Restructuring (CR) is an effective intervention for hostility, the number of patients who fail to benefit suggest that the efficacy of CR can be further improved. The present study investigated whether enhancing CR with mental imagery techniques can increase its efficacy. For the current study, a high hostility sample (28% male, and 72% female) was randomized over one session of imagery enhanced CR (I-CR) (n = 34), traditional CR (n = 32) or an active control session (AC) (n = 21). Changes in hostile beliefs, aggressive tendencies, state anger and hostility traits were assessed pre- and post-treatment, and at one-week follow-up. Results showed that both I-CR and CR efficaciously reduced hostile beliefs, aggressive tendencies and anger, to a stronger degree than AC. I-CR was more efficacious and sustainable over time than both CR and AC in reducing hostile beliefs and aggressive tendencies. Overall, findings suggest that implementing imagery techniques in CR for hostile beliefs enhances its’ efficacy. We will also present explorative data on the potential working mechanisms for I-CR, that we assessed by analyzing the individual I-CR sessions. The results of this study can inform clinical practice on how to effectively target hostility via imagery techniques. Target Audience Beginners, intermediate, and advanced-level participants