A 53-year-old woman was admitted to our hospital due to high fever, arthralgia and skin rash. Main laboratory data included the following: WBC 17, 100/mm, GOT 58 U, GPT 47 U, LDH 1, 510 U, ferritin 19, 000 ng/ml, adenosine deaminase 79.1 U/l. She was diagnosed as having adult-onset Still's disease. Aspirin (3.0 g/day) and prednisolone (40 mg/day) were administered. All the symptoms and laboratory data improved rapidly. Adenosine deaminase, ferritin, and LDH are considered to originate mainly from the liver. Liver injury in this disease may be a primary lesion, and various serum markers may be associated with the liver abnormalities.