Five cases of supravalvular aortic stenosis (SAS) diagnosed by heart catheterization were studied in the Instituto Nacional de Cardiologia of Mexico. The clinic and laboratory data of interest of the differential diagnosis with other forms of obstruction of the left ventricle as follows: 1. Three cases had mental retardation and "elfin" face (SAS with specific psychophysical syndrome), the rest had a normal psyco-physical state without family antecedents (sporadic SAS). 2. The aortic focus was the epicenter of the expulsion murmur. In the phoncarodiographic study, two patients had protosistolic click and another had, in addition, a descending protodiastolic murmur (Int. I-IV). In the radial sphigmograms, one case had an amplitude difference in favor of the right side. 3. All had serum calcium figures within normal limits. 4. A chromosomatic analysis of preperipheral blood was performed on two patients, with normal results. 5. In the electrocardiogram, one case had right ventricular enlargement secondary to pulmonary arterial hypertension, due to stenosis of the main pulmonary arteries. 6. The radiologic study did not show dilatation of the ascending aorta and aortic bud in any case. 7. The angiocardiography showed: stenosis directly above the Valsalva sinuses; absence of dilatation or hypoplasia of the aorta above the stenosis; and the coronary network, indirectly opaqued, showed no abnormalities. One case had aortic coarctation and abnormal implantation of the right sublaviar artery, and another, stenosis of the right and left branch of its origen of the truncus of the pulmonary artery. The literature up to the present is reviewed and an anatomo-functional classification is proposed with the objective of including new varieties.