Factor X deficiency is a rare hereditary coagulation disorder. We report a case of congenital factor X deficiency diagnosed preoperatively in an 8-yr-old female child scheduled to undergo corrective surgery for congenital thoracolumbar kyphoscoliosis. Her preoperative coagulation profile revealed prolonged prothrombin time and activated partial thromboplastin time values. Further evaluation showed functional activity of factor X was <8% of the normal activity and was corrected to 10%-40% of the normal activity with fresh frozen plasma. IV tranexamic acid was also administered to reduce intraoperative blood loss. There were no postoperative bleeding complications. This case emphasizes the need for routine preoperative coagulation screening, at least for major surgical procedures.