Still's disease is a rare multifactorial disease associated with systemic inflammation. Systemic-onset juvenile idiopathic arthritis and adult-onset Still's disease are both pediatric and respectively adult forms of the disease with a cut-off age of 16 years. The disease is characterized by the following features : hectic fever > 39° C, arthralgia or arthritis, rash, neutrophilia and systemic inflammation. The prognosis of the disease is functional and vital. The evolution over time is variable : regression, evolution by relapses with regression at term and chronic joint evolution. This focus describes the two forms of the disease, their complications and the therapeutic options.