Prehospital delay in patients experiencing symptoms of acute coronary syndrome (ACS) has proved to be a significant and intractable public health problem, with minimal change in delay time over the past 2 decades despite numerous community education programs designed to reduce delay. With each 30-minute increment of delay, 1-year mortality increases by 7.5%, thus reinforcing the importance of helping patients label symptoms correctly and take appropriate action steps to seek definitive treatment. We therefore are conducting a multicenter, international clinical trial in 3,500 patients with documented coronary heart disease to determine whether a brief education and counseling intervention delivered by a nurse can reduce prehospital delay in the face of symptoms of ACS. The main outcome being studied is time from ACS symptom onset to arrival at the emergency department. Secondary outcomes include use of the emergency medical system; aspirin use; and knowledge, attitudes, and beliefs about heart attack symptoms. Patients are being followed for 2 years from the time of enrollment. The purpose of this article is to describe the intervention and its theoretical framework, and to outline the design of this randomized controlled trial.