Iodinated radiographic contrast agents (IRCA) are pharmaceuticals commonly used for improving the visibility of internal organs and structures in X-ray based imaging techniques such as radiography, angiography and contrast-enhanced computed tomography scans, and for performing cardiac catheterizations and percutaneous coronary interventions. Like all other pharmaceuticals, however, these agents are not completely devoid of risk. The main risk is their nephrotoxicity. Following the description of Contrast-Induced Nephropathy (CIN) and its pathogenesis, the conditions favoring the development of CIN are discussed in depth. The main predisposing condition is a pre-existing renal impairment, particularly when associated with diabetes mellitus. Then, measures to prevent CIN are suggested. The important rules in CIN prevention are: monitoring renal function, discontinuation of potentially nephrotoxic drugs, use of either iodixanol or iopamidol at the lowest dosage possible. Above all, the main procedure for prevention of CIN is an adequate hydration of the patient with either isotonic sodium chloride or sodium bicarbonate solutions.