Introduction: Choledocholithiasis is the presence of gall stones within the biliary tree which can lead to obstructive jaundice. Alkaline phosphatase, an enzyme secreted by the biliary canalicular cells, is reflective of bile obstruction. Aims: This study aims to identify the dependability of Alkaline phosphatase in predicting choledocholithiasis by assessing sensitivity, specificity, predictive values, false positive and negative values. Methodology: A retrospective, cross-sectional study carried out in Sri Ramachandra Institute of Higher Education and Research, Chennai. The sample size was calculated to be 162 based on the sensitivity (75%) and specificity (37%) of Alkaline phosphatase,1 using a precision of 10% and a confidence interval of 95%. 162 patients who had undergone Magnetic Resonance Cholangio-Pancreatogram (MRCP) from January to December 2019. Results: Of 162 patients who had undergone MRCP,72 (50.39 __ampersandsignplusmn; 16.487) had choledocholithiasis and 90 (49.92__ampersandsignplusmn; 14.875) had other pathologies. Graphical representation of the ALP values revealed that the area under the curve in ROC was found to be 0.641. A clinical cut-off of ALP as __ampersandsigngt;130IU/L had a sensitivity of 70.8% and specificity of 48%. Conclusion: ALP having a low specificity, combined with a normal value in a significant number of patients can lead to a missed diagnosis of choledocholithiasis. The non-universal practice of intra-operative cholangiogram and MRCP adds to these numbers. Hence, more widespread use of MRCP without a selection bias based on ALP values is advocated for suspected choledocholithiasis or bile duct pathologies.