BACKGROUND The development of new small guiding catheters with large internal lumen has allowed their use in routine coronary angioplasty. OBJECTIVE The aim of this study is to present the technical characteristics, results and complication rates obtained with the use of 6 French guiding catheters compared with those obtained with the use of 8 French. METHODS During a 23 month period, a total of 355 consecutive patients was enrolled in this study. Coronary angioplasty was performed in 177 of them using a 6F guiding catheter and 178 using an 8F. RESULTS We found no differences in technical characteristics between both groups: Radiation time (15.7 +/- 14 min vs 16.2 +/- 14 min), guiding catheter to patient ratio (1.1 +/- 0.3 vs 1.06 +/- 0.2), number of balloon catheters per patient (1.2 +/- 0.7 vs 1.36 +/- 0.7). There were no differences in the results obtained (Success 93% in 6F group vs 91% in 8F), major complication rates (Death 0.5% vs 1.6%, CABG 1.1% vs 2.2% or AMI 0% vs 2.2%), or peripheral complications. CONCLUSIONS In coronary angioplasty, with the use of 6F guiding catheters the same results can be achieved as with the use of larger catheters without an increase in technical difficulties or in complication rates.