Williams-Beuren syndrome (WBS) is a rare developmental disorder characterized by distinctive facial, neurobehavioral, and cardiovascular features. WBS is caused by a heterozygous contiguous gene microdeletion of the WBS crítical region on chromosome 7q11.23. Confirmation of clinical suspicion is essential for clinical monitoring of the patient and genetic counseling of the family. Fluorescence in situ hybridization (FISH) is considered the gold standard technique for detecting WBS. Multiplex ligation-dependent probe amplification (MLPA) has been introduced into DNA diagnostic laboratories for the detection of copy number variations in several diseases including WBS. The objective of this study was to confirm, by MLPA, the clinical diagnosis of WBS in a pediatric patient. This technique allowed to detect the deletion of CYLN2, FZD9, STX1A, ELN, LIMK1 and RFC2 genes. In geographic regions were the detection by FISH is not available for this disease, the MLPA methodology allowed to confirm the clinic diagnostic of WBS. To our knowledge this is the first report demonstrating the confirmation of WBS by MLPA in Argentina.