Background:Few large-scale studies have examined the relationship between bleeding events not related to coronary artery bypass grafting (CABG), and the vascular access route used in acute coronary syndrome (ACS) or in elective treatment of coronary artery disease (CAD).Methods and Results:We compared the incidence of bleeding events occurring up to 3 days after percutaneous coronary intervention (PCI) or loading dose of prasugrel or clopidogrel in 2 studies of Japanese patients (PRASFIT-ACS, femoral and radial routes, n=683 and 531; PRASFIT-Elective, femoral and radial routes, n=135 and 508). Rates of periprocedural bleeding, bleeding not related to CABG, and puncture site bleeding were consistently lower in the radial access route group than in the femoral access route group in both studies. Risk factors for periprocedural bleeding included sex, body weight, age, and access route in PRASFIT-ACS (femoral access: hazard ratio [HR], 3.739; 95% confidence interval [CI]: 1.727–8.094; radial access: HR, 0.288; 95% CI: 0.128–0.65), and body weight, age, and access route in PRASFIT-Elective (femoral access: HR, 12.32; 95% CI 1.282–>100; radial access: HR, 0.125; 95% CI: 0.013–1.205).Conclusions:The incidence of periprocedural bleeding is lower with a radial access route than with a femoral access route for PCI in Japanese patients with ACS or those undergoing elective PCI for CAD. (Circ J 2015; 79: 1928–1937)