A very rare case of congenital adrenocortical insufficiency accompanied with ventricular septal defect, is presented. Surgical treatment together with glucocorticoid replacement therapy was performed. The patient, a 4-month-old girl with congenital adrenocortical insufficiency, had been treated with a long-term adrenocortical hormones replacement. Surgical treatment for ventricular septal defect was applied in order to reduce the risk of heart failure. The administration dose of glucocorticoid was determined according to the body surface area and chronologic change of serum cortisol. Following the surgical treatment, and with adequate glucocorticoid replacement, the patient showed a good clinical outcome. In conclusion, we showed a beneficial treatment protocol with adequate glucocorticoid replacement in open heart surgery for a case of congenital adrenocortical insufficiency.