Congenital complete atrioventricular block is uncommon, and the outlook is usually regarded as favourable. Thirty-five patients with congenital heart block are presented. There was no obvious sex difference and their ages ranged from 12 days to 85 years, though most were under the age of 20 years when first seen. Accompanying heart disease was noted in six, but presentation with symptoms in early infancy was a more serious risk factor in our experience. Permanent pacing was required in 21, three of whom were neonates. One of the 14 unpaced patients died unexpectedly at the age of 5 years. Long term supervision is necessary, as most will require permanent pacing before their 50th birthday.