To clarify the clinical pictures of adult Still's disease, 228 cases reported in the past 15 years since Bywaters' first description were reviewed. These included our 9 new cases and an additional 25 cases from the Japanese literature, none of which had been described in previous English reviews. Most of the patients with long followup showed frequent recurrences. About one third developed deforming arthritis with ankylosis. There were 6 deaths. Of interest was the remarkably elevated levels of serum ferritin and prostaglandin E1 in some patients.