Ingestion of ethylene glycol may be an important contributor in patients with metabolic acidosis of unknown cause and subsequent renal failure. Expeditious diagnosis and treatment will limit metabolic toxicity and decrease morbidity and mortality. Ethylene glycol poisoning should be suspected in an intoxicated patient with anion gap acidosis, hypocalcemia, urinary crystals, and nontoxic blood alcohol concentration. Fomepizole is a newer agent with a specific indication for the treatment of ethylene glycol poisoning. Metabolic acidosis is resolved within three hours of initiating therapy. Initiation of fomepizole therapy before the serum creatinine concentration rises can minimize renal impairment. Compared with traditional ethanol treatment, advantages of fomepizole include lack of depression of the central nervous system and hypoglycemia, and easier maintenance of effective plasma levels.