Angiograms from 1,043 consecutive patients undergoing right coronary artery angioplasty were reviewed to determine the incidence of "shepherd's crook" origin of the right coronary artery. Primary results, complications, and technical difficulties were compared with a control group. Fifty-one patients (4.9%) were found to have this anatomic variation. Compared with a control group, the primary success rate was lower (86% vs. 98%) and the incidence of procedural difficulties was higher (33% vs. 13%). Technical problems led to the use of more guiding catheters and more guidewires per patient than in the control group. Thus, coronary angioplasty of shepherd's crook right coronary artery imposes technical problems and is associated with less than an optimal primary success rate.