To report the presence of type B lactic acidosis and insulin-resistant hyperglycemia following cardiopulmonary bypass in a pediatric patient.Case report.Tertiary referral children's hospital pediatric intensive care unit.Fourteen-year-old child with hyperlactatemia and hyperglycemia following cardiac surgery.We report a patient who following cardiopulmonary bypass for repair of his congenital heart disease developed type B lactic acidosis and hyperglycemia resistant to insulin therapy. Resolution of his hyperlactatemia and hyperglycemia occurred approximately 24 hrs postoperatively without apparent ill effect.Type B lactic acidosis is a phenomenon that may occur in the pediatric population in conjunction with insulin-resistant hyperglycemia. We observed that its resolution corresponded to improvement in the patient's hyperglycemia.