Choledochal lithiasis can be suspected in some cases due to the presence of micro calculi (<5mm) in the gallbladder, long-standing gallstones or advanced age of the patient, with about 5% having "unsuspected choledochal lithiasis". In some cases, it presents only as biliary colic, and choledochal lithiasis is an incidental finding on imaging studies or during cholecystectomy. Ultrasound is the most widely used initial imaging method, it has high specificity (95%), but low sensitivity (25-30%), so in some cases other imaging methods are required to confirm the diagnosis, such as cholangioresonance or intraoperative cholangiography. Treatment allows ERCP on the one hand followed by laparoscopic cholecystectomy or bile duct exploration during laparoscopy. Male, 60 years old, with biliary colic, no history of jaundice, normal blood count, normal bilirubin, slight elevation of alkaline phosphatase, and normal amylasemia. The ultrasound shows images of gallstones and 4mm and 5mm lithiasis images in the distal third of the common bile duct of normal caliber (5mm). Cholangioresonance confirms the finding. It is performed by ERCP extraction of two 7 mm stones, with clear bile drainage to the papillotomy. At 48 hours laparoscopic cholecystectomy without problems. Hospital discharge 24 hours later in good clinical condition. Ultrasound is a valuable diagnostic method in patients with unsuspected asymptomatic choledochal lithiasis. Regarding treatment, there is still no consensus on the best strategy and when choosing it is advisable to take into account accessible resources and that it be an effective treatment.