Myocardial injury following elective percutaneous coronary intervention (PCI) occurs in about one-third of patients and is associated with mortality. Platelet aggregation, thrombosis formation, and inflammation are the main causes of cardiac injury during PCI. Vitamin D plays a key role in the cardiovascular system by exerting antiplatelet, anticoagulant, and anti-inflammatory properties. There is no published study that investigated the effect of vitamin D in the prevention of cardiac injury following elective PCI. In a randomized clinical trial, 99 patients admitted for elective PCI were randomized into vitamin D (n = 52) and control (n = 47) groups. The intervention group received 300 000 IU vitamin D orally 12 hours before PCI. The cardiac biomarkers were checked at baseline, 8 and 24 hours after PCI. hs-CRP was also measured at baseline and after 24 hours. The increase in CK-MB was documented in 20 patients (42%) in the control group and 18 patients (34.6%) in the intervention group (P = .417). Furthermore, the increase in cTnI occurred in 4 patients (8%) and 2 patients (3.3%) in the control and intervention groups, respectively (P = .419). No significant changes were noted in the level of cardiac biomarkers. In the vitamin D group, the mean difference in CK-MB between 8 and 24 hours was significantly lower (P = .048). The mean difference in hs-CRP was significantly lower in the vitamin D group (P = .045). This study could not show a clear effect of vitamin D in the prevention of cardiac injury during elective PCI. Further outcome-based studies are needed to describe the role of vitamin D in the prevention of periprocedural myocardial injury..