Contrast media-associated nephrotoxicity continues to be a common cause of acute renal failure. We review recent developments in our understanding of the pathogenesis of this complication, focusing on the role of vasoactive substances which include adenosine, endothelium-derived relaxing factor, and endothelin. An overview of clinical features is presented with an emphasis on the value of low osmolar contrast media in azotemic patients. Prophylactic strategies are reviewed focusing on saline hydration alone, vasoactive pharmacological agents, theophylline, 'prophylactic hemodialysis', and possible differences in how these maneuvers affect diabetic and non-diabetic azotemic patients are discussed.