Magnetic resonance cholangiopancreatography (MRCP) is increasingly replacing diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the initial assessment of patients suspected biliary obstruction, 1 with ERCP being reserved for the removal of confirmed stones in choledocholithiasis.2 However, the optimum method of investigating suspected common bile duct stones is still under debate. MRCP has been shown to be sensitive and specific in the evaluation of choledocholithiasis when compared to ERCP. [3][4][5][6] It is generally well tolerated 7 and avoids the potential complications of ERCP when used as a diagnostic modality. It has high sensitivity and specificity in the initial evaluation of patients with clinical obstructive jaundice and could replace the direct cholangiography when is used for diagnostic purpose.8 However, the value of information gained at MRCP may be limited if patient selection is inappropriate. The role of routine operative cholangiography is also debated with proponents advocating its use in all cholecystectomies in order to reduce bile duct injuries.10 A move to a more selective approach has also been recommended and has been show to be safe, cost effective and not to increase postoperative complications.11 Its role in identifying uncertain anatomy and visualising choledocholithiasis is well established.12 However, whether IOC provides useful additional information following a normal pre-operative MRCP, when at operation the anatomy is judged to be clear, is not known.When compared with direct cholangiography, (ERCP, PTC and IOC), MRCP has again found to be both sensitive and specific. However, in these studies the numbers of IOCs included have been very small, 3,13,14 and the question of whether a pre-operative MRCP can obviate the need for IOC still remains. We, therefore, conducted this prospective study comparing routine IOC with pre-operative MRCP.