Epidemiological studies suggest a higher prevalence of congenital malformations in children conceived through assisted reproductive technologies. There are a few studies that address CHD specifically and most have examined data from registries. We examined the relationship between CHD and assisted conception using data collected in a specialist paediatric cardiac service in the United Kingdom. Between April, 2010 and July, 2011, the parents of children attending paediatric cardiology clinics at the Royal Brompton Hospital, London, were invited to complete a questionnaire that enquired about the nature of their child's conception, the route for their original referral, and a number of potential confounding exposures. "Cases" were defined as children diagnosed with one or more carefully defined CHDs and "controls" as those with normal hearts. Of 894 new attendees with complete data, half of them were cases (n=410, 45.9%). The overall prevalence of assisted conception was 5.4% (n=44). Logistic regression analysis demonstrated a non-significant increase in the crude odds for the use of assisted reproduction (odds ratio 1.21, 95% confidence interval 0.66-2.22) in this group. After adjustment for gestation, parity, year of birth, and maternal age, the odds ratio reduced (odds ratio 0.95, 95% confidence interval 0.48-1.88). Increased rates of assisted conception were observed in a number of CHD subgroups, although no significant differences were found. These findings do not suggest an overall association between CHD and assisted reproduction in this population.