Purpose: The aim of this study was the follow-up of children with a prenatal diagnosis of tachyarrhythmia up to an age of 5 years in order to assess the long-term outcome of these children. Materials and Methods: All fetuses diagnosed with prenatal tachyarrhythmia between April 1993 and June 2004 in the Division of Prenatal Medicine, Department of Obstetrics and Gynecology, University Hospital of Schleswig-Holstein, Campus Lübeck were identified and the childrens parents and pediatricians were contacted for retrospective data on the childrens health. The data from the compulsory examinations (U1 U9) were used for analysis. Results: 49 cases (93 %) were enrolled in this study. 23 fetuses had supraventricular tachycardia (SVT), 10 had an atrial flutter (AF) and 16 had paroxysmal supraventricular tachycardia (pSVT). Intrauterine conversion into sinus rhythm was achieved in 41 of 44 treated fetuses (93 %). 17 of 48 cases showed tachyarrhythmia postnatally (35 %). 15 of these newborns were treated with antiarrhythmic medication between 4 days and 46 months. The follow-up rate in the 3 subgroups ranged from 78 100 %. At the time of the U 9 examination, 69 100 % of the children were healthy. During the examinations there was an increase in motor activity delay and language development delay with a maximum at U 5 and U 9, respectively. Conclusion: Overall, on the basis of the long-term follow-up of 49 children, we could show that prenatal tachyarrhythmia has a good prognosis. Increased motor activity and language development delay are important for patient counseling. Substantial cardiac and extracardiac anomalies are associated with an unfavorable outcome.