In hypoplastic right ventricle the dysplasia of the tricuspid valve (TV) has repercussions on the development of the right ventricle. This paper documents the results of an anatomopathologic and morphometric studies of the tricuspid valve and the right ventricle in 25 hearts with this cardiopathy, which were morphologically analyzed using the segmentary sequential system. The following measurements were made: the annulus of the tricuspid valve, the thickness of the walls of the right ventricle, the ventricular septum and the distances from the atrioventricular-apex (AV-A) and from the apex-pulmonary valve (A-PV). The values obtained were compared with those of normal hearts of equivalent ages; the morphologic features of the tricuspid valve and the right ventricle were described. The thickness of the anterior and posterior walls of righ ventricle was between 2 and 10 times greater than normal. The tickness of the ventricular septum was 1 to 3 times greater than normal and the anterior wall of the infundibulum from 1 to 4 times greater than normal; the AV-A and A-PV distances were reduced in a half of the normal length. The great reduction of the right ventricular cavity was found to be related to the great hypertrophy of the right ventricular walls. The TV was dysplastic with Ebstein's anomaly (72%). The size of the tricuspid valve was small and it was a good indicator for the size of the right ventricle. Morphometric studies are useful because they quantitatively document alterations in the dimensions of valves, walls and diameters of the cardiac chambers in congenital heart disease.