Adult onset still's disease (AODS) is a rare disease (incidence; 0,16 per a hundred thousand) the etiology of which is unknown. It is a systemic inflammatory connective tissue disease which has the same clinic and laboratory features as Juvenile Chronic Arthritis (JCA) in the children above 16. Macrophage-activation Syndrome (MAS) is seen approximately in the 10 % of the patients with Still disease. Being the classial findings of the disease, typical fever over 39, rash and articular involvement affect many organs. Different treatment protocols are applied for the treatment of MAS and the response to the treatment may differ. Despite the treatment, the rate of mortality is around 50 %. We present a case with AODS accompanying with MAS who was treated successfully with mini-pulse steroid and methotrexate therapy. We considered the clinical and laboratory findings enough for our case and we were not in favour of performing bone marrow aspiration which is an invasive method.