Here we report the cytogenetic and clinical manifestations observed in a patient with a rec(20)dup(20p)inv(20)(p11.2q13.3)mat. The patient was a full-term newborn girl with asymmetric intrauterine growth restriction and multiple congenital malformations, including a ventricular septal defect, pulmonary atresia, ambiguous genitalia, clinodactyly, and sacral dimpling. To our knowledge, this is the 4th report in the world and the 1st one in Korea of a patient with rec(20)dup(20p).