The clinical syndrome of unstable angina causes great concern to clinicians because of the high risk of progression to myocardial infarction or cardiac death. Management of unstable angina pectoris has evolved progressively, and recently coronary angioplasty has been shown to be a relatively safe and effective treatment of unstable angina. The aim of this study was to report our experience with the immediate and one year follow-up results of percutaneous transluminal coronary angioplasty (PTCA) in patients with unstable angina. Unstable angina was defined as prolonged periods of chest pain at rest, associated with ST-T changes and no subsequent myocardial necrosis. All patients were treated with a combination of nitroglycerin, beta-blockers or calcium antagonists. The patients were classified into three clinically relevant subgroups. Group I: unstable angina stabilized with pharmacological treatment but with persistent exertional angina (71 patients): group II: unstable angina refractory to optimal pharmacological treatment (88 patients) and group III: recurrent unstable angina within 30 days of myocardial infarction (53 patients). The initial success rate was 87 p. 100 for group I, 92 p. 100 for group II and 89 p. 100 for group III and the major complication rates were 13 p. 100, 8 p. 100 and 11 p. 100 respectively. At 1 year follow-up after initial successful PTCA late death had occurred in 2 p. 100 in group I, 1 p. 100 in group II and 0 p. 100 in group III and a late nonfatal infarction in 2 p. 100, 1 p. 100 and 4 p. 100 respectively. The frequency of recurrent angina was 23 p. 100 in group I, 20 p. 100 in group II and 26 p. 100 in group III. Thus, coronary angioplasty for unstable angina can be performed with a high initial success rate, but at an increased risk on major complications. The prognosis after an initial successful coronary angioplasty is favourable.