A male patient receiving azathioprine treatment for discoid lupus erythematodes developed severe cholestatic hepatitis between 14 and 21 days after initiation of the treatment with peak bilirubin levels of 62.4 mg/dL. Other causes of hepatic dysfunction including viral hepatitis were clinically and serologically excluded. Liver biopsy revealed cholestatic hepatocellular damage. At 14 days after discontinuation of azathioprine the liver function (transaminases and bilirubin) began to improve. Only alcaline phosphatase and gamma-glutamyl transferase remained elevated even after 4 months. This case argues for an idiosyncratic cholestatic hepatocellular damage caused by azathioprine.