Between January 1987 and June 1992 we performed 189 PTCA procedures in a group of 153 patients (127 men, 26 women) aged 28 to 69 years, mean 52.3. 203 coronary vessels were dilated. In 136 pts one vessel was dilated, one vessel with two narrowings were dilated in 16 pts and in 17 pts two-vessel PTCA was performed. Due to restenosis, PTCA was repeated, once in 26 pts, twice in 3 pts and three times in 1 patient. Effective dilatation was achieved in 81.8% of cases and in this number, circumflex and marginal branch of left coronary artery were successfully dilated in 90.7%, left anterior descending in 84.6%, right coronary artery in 84.2% of cases. Attempts to recanalize these vessels were effective in 52%. There were no lethal complications of PTCA, acute occlusion of artery occurred in 5.9% of dilated vessels. Emergency coronary bypass had to be performed in 5.2% pts due to acute artery occlusion. PTCA supported by surgical stand-by appears to be a safe procedure with high direct effectiveness.