Nephrotoxicity from contrast agents is a predictable cause of acute renal failure. Patients at highest risk have both chronic renal insufficiency and diabetes mellitus. Patients with chronic renal insufficiency without diabetes mellitus are also at significant risk. The benefits of coronary angiography must outweigh the risk for each individual patient. Based on available data, our approach to try to reduce the incidence of CIN precipitated by coronary angiography includes discontinuing coadministration of nephrotoxic agents, hydrating the patient with intravenous 0.45% saline, pretreating with acetylcysteine, using low-osmolality contrast media and minimizing the amount of contrast media. Convincing evidence is lacking that other preventive measures (eg, dopamine, furosemide, mannitol, aminophylline/theophylline, ANP, calcium channel blockers, endothelin antagonists) are beneficial. In patients who develop CIN, the renal impairment is usually mild and self-limited. Typically, only supportive care is needed, with a small percentage of patients requiring temporary dialysis. Despite the mild degree of renal impairment, patients who develop CIN have longer hospital stays and have increased in-hospital and 1-year mortality compared with patients who do not develop CIN. Further research, especially with acetylcysteine and endothelin antagonists, is needed to find measures to protect patients against the development of CIN after coronary angiography.