Objectives: People suffering from posttraumatic stress disorder (PTSD) often experience distressing traumatic memories. Therapeutic methods that apply a secondary task while clients recall a trauma memory may further assist in modifying the vividness and emotionality of the trauma memory and in reducing intrusions. In this experiment, we aimed to investigate whether the emotional valence (positive vs. neutral) and sensory modality (visual vs. auditory) of a secondary task reduces the vividness and emotionality of the trauma memory and the proactive interference. Method: Sixty PTSD patients exposed to road traffic accident traumas were randomized to one of four groups in a 2 (emotional valence: positive, neutral) × 2 (modality: visual, auditory) design. Participants were then exposed to a positive or a neutral clip that was visual or auditory and were required to recall the trauma memory during exposure to the clip. Vividness and emotionality of the trauma memory and proactive interference were assessed before and after exposure to the clip and at a 1-week follow-up. Results: Results revealed that participants who recalled the trauma memory while exposed to the positive clip reported their trauma memory as being less distressing (but not less vivid) and indicated less proactive interference than did participants exposed to the neutral clip. Nevertheless, modality had no significant effect in attenuating the proactive interference under conditions of modality congruence. Conclusion: Inducing positive emotion while performing a dual task may be an effective module in therapeutic approaches. (PsycInfo Database Record (c) 2021 APA, all rights reserved).