Intravenous and intraarterial contrast media are invaluable tools in the diagnosis of anatomic lesions. However, they have been associated with deleterious renal events, ranging from acute kidney injury (iodinated contrast) to nephrogenic systemic fibrosis (gadolinium-containing agents). Contrast-associated acute kidney injury has a wide incidence, likely due to differences in populations studied, with incidence likely overstated due to comorbid conditions at the time of contrast exposure. Pathophysiology includes hemodynamic and direct toxic effects. Preventative strategies include intravenous saline administration, higher urine pH, and statin administration. Importantly, because of fears of contrast-associated acute kidney injury, practitioners may be selecting only the healthiest patients for contrast exposure. Gadolinium-based contrast agents may cause their toxicity through being unbound from their ligand, and certain preparations may be less harmful than others.