Data on the incidence of congenital heart defects (CHD) in the first year of life were collected on a cohort of infants born between 1981 and 1984 in New South Wales and the Australian Capital Territory. There was a total of 1479 cases among 343,521 births, an incidence of 4.3 per 1000 livebirths. The following results were obtained after restricting the analysis to cases diagnosed definitively by echocardiography, cardiac catheterization, operation or autopsy. A significant association was found between older maternal age and having an infant with CHD, both before (RR = 1.27, CI = 1.13, 1.44) and after (RR = 1.17, CI = 1.02, 1.33) excluding chromosomally related cases. Significant associations were found between having an infant with ventricular septal defect and Italian parentage (RR = 2.50, CI = 1.11, 5.65), and for having an infant with coarctation of the aorta and Lebanese parentage (RR = 3.82, CI = 1.71, 8.52). The incidence of CHD in this Australian population is similar to overseas studies that used comparable diagnostic criteria and ascertainment. An active surveillance system for CHD is recommended as is further investigation of the factors associated with having an infant with CHD.