We investigated the relationship between atrial fibrillation (AF) and contrast-induced nephropathy (CIN) in patients with non-ST-segment elevation myocardial infarction (NSTEMI); 1045 consecutive patients undergoing percutaneous coronary interventions were enrolled. Risk factors for CIN were investigated. Baseline characteristics, except oral anticoagulant use, were similar between patients with and without AF. Patients with CIN show higher presence of diabetes mellitus (DM), coronary artery bypass graft surgery history, Mehran score, baseline creatinine levels, baseline glomerular filtration rate (GFR), peak troponin levels, left ventricular ejection fraction (LVEF), and presence of AF (P < .05). In multivariate logistic regression analyses, the presence of DM (odds ratio [OR], 2.333; 95% confidence interval [CI], 1.222-4.457; P = .010), Mehran score (OR, 1.269; 95% CI, 1.152-1.398; P < .001), baseline GFR (OR, 0,954; 95% CI, 0.944-0.964 P < .001), left anterior descending artery originated infarction (OR, 1.594; 95% CI, 1.061-2.398; P = .025), LVEF value (OR, 0.956; 95% CI, 0.926-0.986; P = .005), and the presence of AF (OR, 3.830; 95% CI, 1.239-11.839; P = .020) were independent predictors of CIN. Atrial fibrillation can be related to CIN development in patients with NSTEMI.