Pleural and pericardial effusions are a common complication after modified Fontan procedures. 1,2 Most of these effusions resolve within the first postoperative month, but in some cases may last longer than a year after this operation. 3 The causes of these effusions include infection, thoracic duct injury, elevated right atrial pressure, hypoproteinemia, renal failure and postpericardiotomy syndrome. Frequently, a cause cannot be identified and the treatment consists mainly of repeated thoracenteses, chest tube placement, diuretics, fluid restriction and, occasionally, pericardiectomy or pleural membrane sclerosing therapy. We describe 2 patients who had pleural and pericardial effusions more than 6 months after modified Fontan procedures. After identifiable causes for the effusions, including postpericardiotomy syndrome, were ruled out and conventional methods of therapy were unsuccessful, each was treated with anti-inflammatory agents. Both patients showed prompt resolution of the pleural effusions with the anti-inflammatory agents, recurrence of effusions after rapid drug tapering, and permanent resolution after slower tapering of the drugs.