Guidewire manipulation through tortuosities is difficult. Straightening a tortuous coronary artery by using a stiff guidewire has been recognized to induce vessel wall shortening referred to as an "accordion phenomenon." With inappropriate identification as dissection or thrombus formation, the risk of performing unnecessary dilation at the pseudo-narrowing site exists. The authors describe here two cases showing the accordion phenomenon induced by a stiff guidewire during successful stenting at a tortuous right coronary artery. In another case, the authors experienced an "accordion phenomenon" at the proximal edge of the Palmaz-Schatz stent implanted in a tortuous right coronary artery. The stent edge was better positioned at the straight portion than at the contour portion in a tortuous coronary artery.