A patient with Behçet's syndrome manifested by optic atrophy, purulent conjunctivitis and orogenital ulcerations presented with a high fever and pericardial effusion. A mixed cryoglobulinemia (immunoglobulin A (IgA)-immunoglobulin G (IgG)) was observed. Treatment with indomethacin resulted in rapid defervescence, resolution of the pericardial effusion and the orogenital ulcerations, and disappearance of the cryoglobulinemia. Discontinuation of indomethacin therapy was followed by a recurrence of the oral and genital ulcerations that responded promptly to the reinstitution of indomethacin treatment.