VACTERL association with a rare vertebral anomaly (butterfly vertebra) in a case of monochorionic twin: The VATER/VACTERL association is typically defined by the presence of at least three of the following congenital malformations: vertebral anomalies, anal atresia, cardiac malformations, tracheo-esophageal fistula, renal anomalies, and limb abnormalities (13). We report a rare case of a monochorionic twin gestation in which one of the infants had VACTERL association. Antenatal ultrasound showed bilateral renal dysplasia and cardiac anomaly (ASD) in twin A. Twin A was noted to have the following anomalies: a single umbilical artery, limb anomaly (right hand preaxial polydactyly), vertebral anomalies (T9 and T11 butterfly vertebras, bilateral renal agenesis, bladder agenesis, anal and urethral atresia. A normal-sized stomach and normal amount of amniotic fluid were observed during the prenatal period with no other anomalies. Twin B (male) was healthy and no cardiac, renal, or congenital anomalies were demonstrated on ultrasound and physical examination. Infant A was also diagnosed as having VACTERL association because he had five of the core anomalies (V, A, C, R, L) of VACTERL association. Butterfly vertebra is an uncommon congenital spinal anomaly. To the best of our knowledge, our patient is the second case VACTERL association with butterfly vertebra in the literature.