Background: Anxiety is commonly present in those at risk for vascular disease and independently contributes to risk of vascular events, morbidity, and mortality. Yet, anxiety is an underappreciated risk factor and effective treatments have rarely been investigated.  Acceptance and Commitment Therapy (ACT) is an empirically supported behavioral therapy that incorporates acceptance and mindfulness strategies with behavioral change modalities. ACT is effective in treating depression and anxiety which are common in patients with cardiovascular disease, as well as illnesses like chronic pain. Importantly, when presented as a brief intervention, ACT has resulted in positive long-term outcomes. Objective: To examine the efficacy of a 1-day (6-hour) Acceptance and Commitment Training group workshop (ACT) compared to Treatment as Usual (TAU) on forearm blood flow and on anxiety symptoms. Method: 55 patients with significant anxiety were randomly assigned to an 1-day ACT workshop or to Treatment as Usual (TAU). Assessment of anxiety and blood vessel flow were completed prior to the workshop and 3 months following the workshop. Results: At the 3-month follow up, participants in the ACT condition exhibited significantly improved forearm blood flow (p < .05) and significantly greater improvements in anxiety symptoms (p < .01) than patients in the TAU group. Conclusion: A 1-day ACT workshop is a promising approach for the treatment of anxiety and may improve vascular disease risk factors. Brief interventions, such as the 1-day intervention developed for this study, offer the potential for optimal treatment adherence, participant acceptability, and broad dissemination.