Percutaneous transluminal balloon coronary angioplasty (PTCA) of coronary bifurcations is associated with a low success rate, high rate of complications, and high incidence of target vessel revascularization (TVR). The strategy of systematic coronary stenting in bifurcation lesions involving a side branch ≥ 2.2 mm in diameter was prospectively evaluated in a single‐center observational study during a 35‐month inclusion period. All patients meeting these criteria were consecutively included. Bifurcation lesions and treatment were predefined in the study. The study included 366 patients (12.1% of PTCA) with 373 bifurcation lesions, mean age 63.7 ± 11.6 years, 79.2% male, 46.7% with unstable angina, and 8.3% acute MI. The left anterior descending/diagonal bifurcation was involved in 55.2% of cases, circumflex/marginal 22.2%, PDA/PLA 10.4%, left main bifurcation in 6.8%, and others 5.4%. The main branch (2.78 ± 0.42 mm reference diameter) was stented in 96.3% of cases and the side branch (2.44 ± 0.43 mm) in 63.2% (the two branches were stented in 59.5% of cases). Procedural success was obtained in 96.3% in both branches and 99.4% in the main branch. At1‐month follow‐up, The major cardiac event rate (MACE) was 4.8% (death 1.1%, emergency CABG 0.6%, Q‐wave MI 0.9%, acute or subacute closure 1.4%, repeat PTCA 1.1%, and non‐Q–wave MI 2.3%). At 7‐month follow‐up, the total MACCE rate was 21.6%, including a TVR rate of 17.2%. Analysis of the 7‐month outcome according to two study periods (period I, 1 January 1996 to 31 August 1997, 182 patients; period II, 1 September 1997 to 30 June 1998, 127 patients) showed that the TVR rate decreased from 20.6% to 13.8% (P = 0.04) and the MACE rate from 29.2% to 17.1% (P < 0.01) in period I and II, respectively. This was associated by univariate analysis with an increasing use of tubular stents deployed in the main branch (94.2% vs. 59.1%, P < 0.001) and kissing balloon inflation after coronary stenting (75.4% vs. 18.1%, P < 0.001). Bifurcation lesions are frequent. Procedural success of coronary stenting is high with a low rate of in‐hospital MACE. TVR rate at follow‐up is relatively low. In‐hospital and follow‐up results are influenced not only by the learning curve but also by the use of tubular stents in the main branch and final kissing balloon inflation. Cathet. Cardiovasc. Intervent. 49:274–283, 2000. © 2000 Wiley‐Liss, Inc.