Multifocal atrial tachycardia (MAT) was observed in 9 patients aged 60-85 (mean 72.1±8.6) years during exacerbation of their chronic lung and/or cardiac disease. Four, in whom the rapid heart rate caused symptoms of pulmonary congestion, were treated with intravenous amiodarone (450-900mg over 2 hours) with restoration of sinus rhythm soon after the termination of the drug infusion. In 1, with recurrence of MAT, the same intravenous dosage was repeated for 2 consecutive days, with final achievement of stable sinus rhythm. Five patients, apart from the conventional management of their underlying disease (digitalis, diuretics, aminophylline) were treated with oral amiodarone (600mg/day). Sinus rhythm was restored in all and remained stable during their hospitalization, under α maintenance dosage of 200-400mg daily. Amiodarone may be the drug of choice for the treatment of MAT, for which up to now no effective therapy has been established.