Nine cases (7 boys and 2 girls) of aneurysm of the sinus of Valsalva (SVA) diagnosed before 19 years of age are reported. Group 1 comprised 5 children aged 5 to 14 years without rupture of the aneurysm; 3 had an associated ventricular septal defect (VSD). The diseased sinus was the right anterior sinus in 4 cases and the posterior sinus in one case. The diagnosis was made by 2D echocardiography, performed in 3 patients for follow-up of a VSD and in 2 patients to investigate a systolic murmur. Group 2 comprised 4 patients under 19 years of age with SVA which ruptured into in the right heart cavities. One of these patients had a known right anterior SVA diagnosed at angiography performed to investigate a VSD when the child was 4 years old. The rupture occurred suddenly when the child was 14. These cases of SVA involved the right anterior sinus with rupture into the right ventricle (3 cases) and the posterior non-coronary sinus with rupture into the right atrium (1 case). A rupture syndrome was observed in 3 of the 4 patients with pulmonary oedema in 2 cases. The authors emphasise the rarity of SVA diagnosed before rupture and the low frequency of rupture before adulthood. Echocardiography is certainly the best method for diagnosing the condition and for following up these patients.