Three successive time periods were compared to study the impact of evolving techniques and new equipment on the immediate results of single‐vessel percutaneous transluminal coronary angioplasty (PTCA), the initial success rate and major complication rate (death, myocardial infarction, and urgent surgery). The three periods were selected on the basis of a significant advance in either PTCA technique or equipment. In period I from 1980 to 1983 a nonsteerable catheter system was used. In period II from 1983 to 1986 a steer‐able catheter was used. In period HI from 1986 to 1987 the long guidewire technique and/or monorail system was used. A total of 1,371 successive patients underwent single‐vessel dilatation for stable angina (848 patients) or for unstable angina (523 patients). Initial success was defined as a reduction of the stenosis to less than 50% with no major complications (myocardial infarction or death, or the necessity of proceeding to coronary artery bypass surgery). The initial success rate increased from 68% (period I) to 88% (period II) and to 91% (period III) for all attempts. When attempts of dilatation of totally occluded vessels were excluded these figures were 71%, 91%, and 95%, respectively. The overall major complication rate decreased from 16% (period I) to 8% (period II) to 3.5% (period III). Thus, increase in investigator experience, technical improvements of balloon catheter systems, and introduction of new PTCA techniques have resulted in an increase in success and safety of PTCA procedures. (J Inter‐ven Cardiol 1