A patient with types A and B of Wolff-Parkinson-White syndrome developed subacute pneumonitis during long-term treatment with amiodarone. The pneumopathy occurred only when the maintenance dose was increased to 800 mg/day. Lung specimens obtained by transbronchial biopsy showed chronic pneumonitis with C3 deposition by immunofluorescence. Pulmonary signs spontaneously disappeared two months after the drug was discontinued.