Danazol, an inhibitor of pituitary gonadotropin, has been proposed in the treatment of systemic lupus erythematosus (SLE). We report the case of a female patient with SLE in whom a hepatocellular carcinoma was discovered after 4 years of treatment with danazol. Except for 3 days of hypochondrium pain, there were neither clinical signs of liver tumor nor biological abnormalities. An ultrasonography showed 2 tumors of the liver. At histological examination after surgery, one of the tumors was found to be a benign adenoma, while the other was a well differentiated hepatocellular carcinoma. When longterm danazol therapy is required, ultrasonography may be useful for early tumor detection.