Background: Contrast-induced nephropathy (CIN) is an iatrogenic problem in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Atrial fibrillation (AF) may also contribute to impaired kidney function. Several factors may contribute to the development of CIN. In patients with STEMI, concomitant AF is associated with higher in-hospital/follow-up mortality and morbidity. Therefore, we aimed to investigate the relationship between AF and CIN developments.