A 3-year-old girl presented with polydipsia, polyuria, hyponatremia, hypertension and congestive heart failure. Her polyuria was unresponsive to water restriction and vasopressin challenge tests, and her blood pressure was not effectively controlled by antihypertensive drugs. Radiologic examinations revealed a Wilms' tumor in the right kidney. Her plasma renin activity and aldosterone concentration were greatly increased. After surgical removal of the tumor, the congestive heart failure disappeared. Congestive heart failure due to Wilms' tumor is very rare and we report here on such a case, with a brief review of the literature.