Lambl's excrescences have a low prevalence in the general population. Although they occur most frequently in adults over 60 years-old, pediatric cases have been described. The cases in adulthood are associated with ischemic stroke, but in childhood they are asymptomatic. The aim of reporting on this case series is to show the association or coexistence of Lambl's excrescences with some congenital heart diseases (CHDs), of which there are no known descriptive case series in adults or children. We present 17 patients (8 females), with a mean age of 23.7 years; among these cases, 64.7% were under 18 years-old. We found that 94% of the Lambl's excrescences were located on the aortic valve. In 47% (8 cases), they coincided with a CHD (with 6 of those individuals being under 18 years-old). We propose the hypothesis that Lambl's excrescences could have a congenital origin or coexist with CHD. No complications were found throughout the follow-up. Lambl's excrescences could be more frequent than currently reported in the literature, and more research should be done on their significance in CHD-associated stroke.