Coronary angioplasty is an effective recanalization technique, but is plagued by a high restenosis rate. One of the major effects of balloon dilatation is the stretching of the vessel wall and the subsequent elastic recoil. Although a well known phenomenon, few data have been published on the evaluation of elastic recoil after coronary angioplasty. The purpose of this study was to quantify the acute and short-term elastic recoil after coronary dilatation. Thirty-six patients underwent coronary angioplasty. A digital end-diastolic acquisition of the coronary artery was performed before, immediately after, at 15 min and at 20 hours after dilatation. Elastic recoil was defined as the difference between the diameter of the inflated balloon and the diameter of the vessel after dilatation. It was quantified by a semi-automatic computer-assisted program. Our data show a high elastic recoil immediately after dilatation, equal to 27.9% (p < 0.0001), which continues for the next 20 hours to a final value of 34.1%. No difference was found in the amount of elastic recoil depending on the coronary artery involved, length, severity and eccentricity of the stenosis, time and pressure used during balloon inflation. Elastic recoil was more pronounced (p = 0.002) using balloons with a balloon diameter/vessel diameter ratio > 1.