BACKGROUND Certain congenital cardiac defects may go undetected for several years due to lack of symptoms and signs. Our purpose was to determine the prevalence of such defects among children greater than one year of age. METHODS The study was performed on subjects diagnosed with systemic hypertension, aged from 1 to 19 years, with a mean of 12.4 years, in whom we performed echocardiography, using a standard protocol, to establish any end-organ damage or to reveal any congenital cardiac defects. RESULTS We found a congenital cardiac defect in 5 (3.5%) of the 143 children evaluated. Of these, 4 had not previously been detected, specifically Ebsteins malformation of the tricuspid valve, with moderate regurgitation, a coronary arterial anomaly, a bicuspid aortic valve, and prolapse of the mitral valve permitting regurgitation. In the other patient, we found a non-significant tiny muscular ventricular septal defect. CONCLUSIONS Our transthoracic echocardiographic investigation revealed previously unsuspected congenital cardiac defects in 4 of 143 older children, with 3 of these requiring further management by a paediatric cardiologist. A similar prevalence has also been reported in older children evaluated echocardiographically for other diseases such as insulin-resistance and leukemia. Hence, it is possible that the prevalence of congenitally malformed hearts is higher than previously reported. When clinically indicated, clinicians should more readily consider obtaining an echocardiogram to help in the identification of such malformations.