In patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention, contrast-induced nephropathy (CIN) is a serious complication associated with poor outcomes. We assessed the predictive value of the Canada Acute Coronary Syndrome (C-ACS) score for CIN in these patients. A total of 394 consecutive patients with STEMI were enrolled and divided into 3 groups according to their C-ACS scores—group 1, score 0; group 2, score 1; and group 3, score ≥2. The clinical outcomes were CIN and major adverse clinical events (MACEs) during hospital and follow-up; 8.4% of patients developed CIN. Patients with high C-ACS scores were more likely to develop CIN, in-hospital death, and MACEs (P < .001). The C-ACS score was an independent predictor of CIN (odds ratio = 2.87; 95% confidence interval = 1.78-4.63; P < .001) and risk factor for long-term MACEs. The C-ACS score had good predictive values for CIN, in-hospital morality, MACEs, and long-term mortality. Patients with high C-ACS risk scores exhibited a worse survival rate than those with low scores (death, P = .02; MACEs, P = .006). In conclusion, in patients with STEMI, the C-ACS could predict CIN and clinical outcomes.