We sought to examine the short- and long-term outcomes of patients who developed contrast-induced acute kidney injury (CI-AKI; defined as an increase in serum creatinine of ≥0.5 mg/dL or a 25% relative rise within 48 h after contrast exposure) from the large-scale HORIZONS-AMI trial. Multivariable analyses were used to identify predictors of CI-AKI, as well predictors of the primary and secondary endpoints. The incidence of CI-AKI in this cohort of ST-segment elevation myocardial infarction (STEMI) patients was 16.1% (479/2968). Predictors of CI-AKI were contrast volume, white blood cell count, left anterior descending infarct-related artery, age, anaemia, creatinine clearance <60 mL/min, and history of congestive heart failure. Patients with CI-AKI had higher rates of net adverse clinical events NACE; a combination of major bleeding or composite major adverse cardiac events (MACE; consisting of death, reinfarction, target vessel revascularization for ischaemia, or stroke) at 30 days (22.0 vs. 9.3%; P < 0.0001) and 3 years (40.3 vs. 24.6%; P < 0.0001). They also had higher rates of mortality at 30 days (8.0 vs. 0.9%; P < 0.0001) and 3 years (16.2 vs. 4.5%; P < 0.0001). Multivariable analysis confirmed CI-AKI as an independent predictor of NACE hazard ratio (HR), 1.53; 95% confidence interval (CI), 1.23-1.90; P = 0.0001, MACE (HR, 1.56; 95% CI, 1.23-1.98; P = 0.0002), non-coronary artery bypass grafting major bleeding (HR, 2.07; 95% CI, 1.57-2.73; P < 0.0001), and mortality (HR, 1.80; 95% CI, 1.19-2.73; P = 0.005) at 3-year follow-up. Contrast-induced acute kidney injury is associated with poor short- and long-term outcomes after primary percutaneous coronary intervention in STEMI.