Wilms'' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is caused by deletion of chromosome 1 1 p1 3 , including the Wilms'' tumor (WT1 ) and aniridia gene (PAX6 ) loci. Here, we report the first case of WAGR syndrome in Korea; the patient was a 2 -year-old girl with bilateral aniridia from birth who presented with abdominal distention and mental retardation. Cytogenetically, she had deletion of chromosome 1 1 p1 1 .2 -1 3 . Bilateral Wilms'' tumors were successfully treated by chemotherapy and surgery. She has been tumor-free for 1 9 months off chemotherapy with preserved renal function. (Kore an J Pe diatr 2 0 0 8 ;5 1 :1 3 5 5 -1 3 5 8 ) Key Words : WAGR syndrome, Wilms'' tumor, Aniridia