Teratoid Wilms' tumor is an extremely rare renal tumor. We report a case of unilateral teratoid Wilms' tumor in a 4-year-old girl. The patient was admitted with a right-sided abdominal mass. The mass was arising from the right kidney. Radical nephrectomy was done and the patient had an uneventful recovery. Histopathology report showed teratoid Wilms' tumor.