The results of many studies on the prevalence of mitral valve prolapse have been greatly influenced by the diagnostic methods and criteria adopted as well as by population selection. The method of choice today is 2d-echocardiography because of its ability to highlight both movement anomaly (i.e. functional prolapse) and any eventual morphological variations of the mitral valve (i.e. anatomic prolapse). The latter (chordae lengthening, thickening and overabundance of the leaflets, dilation of the valvular ring) are, nowadays, considered especially important even as predictive factors of complications. Therefore we studied the prevalence of these two types of prolapse in a population of 420 university students. Functional mitral valve prolapse was found in 27/420 (6.4%) and anatomical prolapse in 2 cases (0.5%). No auscultatory finding was present in 24/27 patients with functional prolapse. There was no correlation between the two types of mitral valve prolapse and the body mass index, the fractional shortening of the left ventricle and symptoms (dyspnea, palpitations, precordial pain, dizziness). We think that the distinction between the two types of mitral valve prolapse should prove very useful for the comparison of results in future epidemiological studies. Follow-up of both groups of patients will hopefully clarify the usefulness of such distinction from the clinical point of view.