We report a case of adult-onset Still's disease (AOSD) revealed by pleuropericardial manifestations. A 40 yr old black woman was admitted for flu-like syndrome with pharyngitis, hectic fever, polymorphonuclear hyperleucocytosis and pleuropericarditis. The diagnosis of AOSD was supported by 3 major and 3 minor criteria after exclusion of infectious, haematological and connective tissue diseases. Pulmonary involvement is infrequent in AOSD, and consists of transient pulmonary infiltrates and chronic restrictive pattern. However, pleuritis, like pericarditis, is present in 25% of cases. Initial onset of pleuritis, associated with fever and hyperleucocytosis preceding articular manifestations could be responsible for a delay in diagnosis and a subsequent worsening in the prognosis of the disease. A rapid improvement is usually observed under nonsteroidal anti-inflammatory drug or corticosteroid treatment.