Choledochoduodenal fistula (CDF) is an abnormal communication between the common bile duct and the duodenum. It accounts for about 5% to 25% of the total biliary fistulas and is usually due to a perforated duodenal ulcer, choledocholithiasis, and complications secondary to tuberculosis or could be iatrogenic. Primary intrabilliary tumors usually cause obstructive jaundice and rarely biliary metastasis arising from other organs like colon, breast, and lungs can cause obstructive jaundice. There has been a case report of metastasis from ovarian cancer to the major papilla of the duodenum but no reported cases of it causing a CDF. We report a rare case of an 83-year-old female with ovarian cancer who developed a metastatic lesion to the duodenum eventually resulting in a CDF.