This retrospective study (1991-95) presents our experience with sotalol in the treatment of 14 foetuses with supraventricular tachycardia (SVT). SVT was diagnosed in a structurally normal heart at a gestational age of 24-35 (median 28) weeks. In eight foetuses, hydrops was evident at presentation. In all patients pharmacological conversion with digoxin was tried before sotalol treatment was started. Sotalol was given orally to the mothers in a dose of 80-160 mg x 2. Cardioversion was obtained in 10 foetuses. In seven of these patients re-entry tachycardia and in five pre-excitation could be documented after birth. In two foetuses not responding to sotalol a long RP tachycardia was demonstrated; even when using digoxin, sotalol, flecainide and/or propafenone in different combinations after birth complete suppression of the arrhythmia was not obtained. Two severely hydropic foetuses died 1 and 10 d, respectively, after starting with sotalol. The 12 surviving infants were doing well except for one infant, with a cerebral lesion probably related to the arrhythmia. These findings demonstrate that sotalol can be useful in the treatment of foetal SVT.