We report on two newborn infants with foetal tachycardia and cerebral lesions. Using foetal echocardiography, the diagnosis of supraventricular tachycardia in a structurally normal heart was made at 28 and 37 weeks of gestation, respectively. One infant had a 3 week period of foetal tachycardia and hydrops before successful pharmacological cardioversion. Even several weeks after a term birth he remained hypotonic and needed gavage feeding. A computed tomography (CT) scan demonstrated cerebral lesions indicating a vascular origin. A possible thrombus was found in the heart. The other infant converted to sinus rhythm during birth by Caesarean section on the day after diagnosis. He had convulsions at the second day of life. On CT scan an infarction was found. The observations of this report suggest that cerebrovascular complications to foetal arrhythmias are more common than previously observed and should be considered when managing cases of foetal tachycardia.