In Order to evaluate determinants of successful percutaneous transluminal coronary angioplasty (PTCA), PTCA was performed for 172 coronary arterial lesions in 120 patients (89 male, 31 female) at Yeungnam university hospital from Sep. 1992 to Aug. 1993. The corinary artery luminal diameter at the site of the original stenosis was eveluated from end-diastolic frames of identical projections of the preangioplasty and immediate post angioplasty. The coronary luminal and balloon diameters were measured with using of computer measuring system. Overall success rate of 172 attempted lesions was 87.2%. Success rate of female patients was 93.5% and higher than those of male patients. According to the clinical diagnosis, success rate in stable angina was 93.7% and higher than those of post myocardial infarction angina, unstable angina and acute myocardial infarcrion. Success rate of American Heart Association type C lesion was 65.5% and lower those of type A (95.7%), type B (89.5%). There was signfifcantly difference in preangioplasty luminal stenosis, elastic recoil and length of lesion between successful PTCA group and failed PTCA group. Success rate of lesion location at a bend > $45^{circ}$ and presence of intracoronary thrombus were lower than than those of other angiographic findings. In coclusion, primary angioplasty success was affected by specific angiographic factors. Stenosis severity, thrombus, lesion location at a bend > $45^{circ}$, elastic recoil, and length of lesion were the principle of determinants of coronary angioplasty success rate.