We retrospectively compared the efficacy of percutaneous transluminal coronary angioplasty (PTCA) and intracoronary thrombolysis (ICT) in patients with acute myocardial infarction (AMI). The ICT group consisted of 62 consecutive patients who underwent ICT before the introduction of PTCA for AMI and who were considered to be candidates for PTCA based on review of their cine-films. The PTCA group consisted of 92 consecutive patients who underwent PTCA thereafter. The reperfusion rate was significantly higher in the PTCA group than in the ICT group (92.4% vs 71.4%, p less than 0.01) and the residual stenosis was significantly lower in the former. Furthermore, the incidences of reinfarction and post-infarction angina were significantly lower in the former than in the latter (3.3% vs 12.9%, p less than 0.05 and 6.5% vs 29.0%, p less than 0.001 respectively). Although the degree of improvement in left ventricular function was influenced by the result of reperfusion, it was not affected by the reperfusion method. Therefore, PTCA did not improve left ventricular function more than ICT unless ICT alone failed to achieve reperfusion.