The Randomised Intervention Treatment of Angina (RITA) Trial is a prospective, randomised study to compare the short term and long term effects of percutaneous transluminal coronary angioplasty and coronary artery bypass surgery. During the study a register of patients undergoing coronary arteriography at the fourteen participating centres is being maintained to assess the overall context of patient recruitment. Patients with arteriographically proven coronary artery disease are considered for the trial if the participating cardiologist and surgeon agree that equivalent revascularisation could be achieved by either treatment method. Patients who satisfy the trial entry criteria are randomised to treatment by coronary angioplasty or coronary artery bypass surgery, with prospective stratification into groups with one, two, or three treatment vessels. Randomisation implies an intention to treat the patient by the assigned procedure and the analysis of long term results will include all randomised cases. The trial will recruit at least 1000 patients who will be followed for five years. The major trial end points include death, new myocardial infarction, and new coronary angioplasty or coronary artery bypass procedures. Other outcome measures include symptom and employment status, quality of life, exercise tolerance, and left ventricular function.