A patient with chronic systemic Weber-Christian disease who was treated with hydroxychloroquine developed cardiac dilatation with congestive heart failure. Endomyocardial biopsy demonstrated myocyte degeneration and interstitial fibrosis, but no typical features of chloroquine induced cardiomyopathy. Clinical symptoms of congestive heart failure also were recognized in 7 of the 11 reported autopsy cases of Weber-Christian disease having cardiac involvement. This involvement can affect the pericardium and the myocardium.