Contrast-induced nephropathy (CIN) is a leading cause of in-hospital acute renal failure in critically ill patients who undergo radiographic procedures. Critical care patients are at particular risk, often because of baseline renal dysfunction, older age, and the presence of diabetes. In addition, there are superimposed risks, including volume depletion, sepsis, and use of nephrotoxic drugs. The rates of CIN (defined as an increase in serum creatinine by >25% or 0.5 mg/dL) can be predicted by using multivariate tools. Prevention measures include adequate hydration, use of N-acetylcysteine and iso-osmolar contrast, and for patients who are at the highest risk, prophylactic hemofiltration.