Skin radiation injuries, especially radiation ulcers, are serious side effects caused by ionizing radiation during percutaneous coronary interventions (PCI). Because skin radiation injuries are closely associated with the peak skin dose, it is important to minimize the peak skin dose. The aim of the present study was to investigate the determinants of greater peak skin dose in current PCI. We included 707 consecutive coronary artery lesions, and divided them into an excess radiation group (n = 26; defined as peak skin dose ≥2 Gy) and a standard radiation group (n = 681; defined as peak skin dose <2 Gy). Clinical, lesion, and procedural characteristics were compared between the 2 groups. Univariate and multivariate logistic regression analyses were performed to identify determinants of the excess radiation group. A multivariate logistic regression analysis revealed that body surface area (BSA) [0.1 m2 increase: odds ratio (OR) 1.39, 95% confidence interval (CI) 1.13-1.71, P < 0.01], PCI to a right coronary artery (RCA) (OR 3.11, 95% CI 1.35-7.17, P < 0.01), and PCI to a chronic total occlusion (CTO) (OR 6.69, 95% CI 2.65-16.87, P < 0.01) were significantly associated with the excess radiation group. Greater BSA, PCI to RCA lesions, and PCI to CTO lesions were significantly associated with excess radiation dose. The first step in the prevention of radiation injuries in current PCI will be to recognize these risk factors.