The syndrome of the mitral valve prolapse is being recognized more frequently in the pediatric age range. The presence of an apical midsystolic click and a late systolic murmur should suggest the diagnosis. When the diagnosis is made, a chest roentgenogram, an electrocardiogram, and an echocardiogram should be performed as a baseline. Activity can be normal. Prophylactic antibiotics are essential before oral surgery. Periodic reexaminations with an electrocardiogram, and, if indicated, a dynamic Holter tracing should be performed. Long-term prognosis remains uncertain, and some caution should be exercised in predicting the future. Because of the known familial incidence of the syndrome, echocardiograms on members of the family should be done and genetic counseling offered to the affected individuals.