Williams syndrome is a rare genetic neurodevelopmental disorder with a characteristic physical and behavioral phenotype caused by deletion at the 7q11.23. It is usually diagnosed in childhood by clinical evaluation when typical facial features, supravalvular aortic stenosis on echocardiography, hypercalcemia and other neurodevelopmental and behavioral profile may become apparent. Conjugated hyperbilirubinemia, posterior embryotoxon, pulmonary stenosis, vertebral anomalies, renal anomalies and vascular anomalies are typical features of Alagille syndrome, which is caused by mutations in or deletion of the JAG1 gene at 20p.12 or rarely the NOTCH 2 gene at 1p12. There may be some overlap in the clinical features between these syndromes; however, conjugated hyperbilirubinemia, posterior embryotoxon and vertebral anomalies are not features of William syndrome. The typical facial features specific to each of the syndromes usually become apparent with age and pose a challenge in making a diagnosis in the newborn period and especially when the baby is premature. We report a preterm newborn with spectrum of clinical features highly suggestive of Alagille syndrome but array CGH consistent with Williams syndrome. To the best of our knowledge, this very unusual association, has been reported only on three occasions in the past and further extend the phenotype of Williams syndrome.