Unrecognized lithiasis of the cystic duct (CDL) may be responsible for post cholecystectomy. This retrospective study looked at the incidence of CDL during cholecystectomy, as well as the context of its occurrence; recommendations for a practical surgical approach are offered. METHODS Over a period of 30 months, 143 consecutive cholecystectomies (103 women, 40 men; mean age: 57 years) were performed by the same surgeon: 142 by laparoscopy, and one by laparotomy due to a history of previous gastrectomy. The cystic duct was always opened and milked upward in search of CDL before immediate clip occlusion or performance of cholangiography (106 times, 74.1%). In seven cases, cholangiography was impossible because the cystic duct was too narrow. RESULTS There was no mortality. CDL was found in 21 cases (14.7%) and removed. This had not been identified by preoperative imaging (ultrasound or CT). Pain in the month preceding cholecystectomy occurred more frequently in cases of CDL (19/21[90.4%] vs 36/122 [29.5%]; P<0.001). Similarly, liver function tests were more often abnormal with CDL (10/21 [47.6%] vs 30/122 [24.5%]; P<0.05). However, neither jaundice nor gallbladder inflammation was predictive of CDL in this study. Echoendoscopy (EUS) was performed more often for suspected common duct lithiasis migration (CBDL) in patients with CDL than for those without (9/21 [42.8%] vs 26/122 [21.3%]; P<0.05). CBDL was present in 12 of 143 patients (8.3%). This was treated by preoperative endoscopic sphincterotomy in 10 cases, and twice by trans-cystic stone extraction during the laparoscopic intervention. CBDL occurred more frequently in association with CDL (5/21 [23.8%] vs 7/122 [5.7%]; P<0.01). In addition, CDL was still present at cholecystectomy in the four patients who underwent preoperative endoscopic sphincterotomy. CONCLUSIONS Cystic duct lithiasis is found frequently during cholecystectomy; CDL is often associated with preoperative pain, abnormal liver function tests and choledocholithiasis. It can persist despite preoperative sphincterotomy. The search for and treatment of CDL should be routinely performed during cholecystectomy.