BACKGROUND: Early detection of congenital heart defects provides better postnatal treatment strategy and prognosis. Therefore, we aimed to determine the frequency of congenital heart defects on fetal echocardiography in high-risk mothers referred to the Children hospital, Lahore. METHODS: A cross-sectional observational study was conducted in the Cardiology department, of Children Hospital, Lahore from July to December 2015. The data were collected from 138 high-risk pregnant mothers. Both maternal and fetal risk factors associated with congenital heart defects were considered for indication of fetal echocardiography. RESULTS: Of the 138 high-risk pregnancies, 131 had maternal and 7 had fetal risk factors. Of the fetuses with maternal risk factors, the prevalence of congenital heart... defects was 6%. We did not find any congenital heart defects in fetuses with fetal risk factors. 2.17% congenital heart defects presented with a history of gestational diabetes mellitus and 3.62% presented with poor obstetric history (p ≤ 0.05). Atrial septal defects and ventricular septal defects each were present in 2 (1.4%) fetuses while 1 (0.72%) fetus had complete atrioventricular septal defect, 2(1.4%) had septal hypertrophies and 1 (0.72%) had pericardial effusion. CONCLUSION: We observed a 6% frequency of congenital heart defects in high-risk mothers. With this high frequency of congenital heart defects, fetal echocardiography should be included as part of second-trimester anomaly scan in all high-risk mothers.