Williams-Beuren Syndrome Detected with Constipation and Murmur Williams-Beuren syndrome (WBS) is a rare disease that occurs as a result of microdeletion of 11.23 of the long arm of chromosome 7, with a frequency of 1/20.000-30.000. Typical facial appearance, mental retardation, various congenital cardiovascular anomalies and endocrinological disorders may accompany this syndrome. In cases suspected as a result of clinical and laboratory findings, the diagnosis is made by showing the deletion of the mentioned region using the fluorescent in situ hybridization (FISH) method. We detected WBS in a 17-month-old male patient who presented with chronic constipation and had peripheral pulmonary stenosis in echocardiography performed with accompanying clinical findings, and aimed to emphasize the importance of multidimensional evaluation and early diagnosis. Keywords: Congenital heart disease, pulmonary stenosis, microdeletion syndromes, constipation, Williams-Beuren syndrome