Background. Abnormal liver enzymes postorthotopic liver transplant (OLT) may indicate significant biliary pathology or organ rejection. There is very little known in the literature regarding the current role of diagnostic ERCP in this scenario. Aim. To review the utility of diagnostic ERCP in patients presenting with abnormal liver function tests in the setting of OLT. Methods. A retrospective review of diagnostic ERCPs in patients with OLT from 2002 to 2013 from a prospectively maintained, IRB approved database. Results. Of the 474 ERCPs performed in OLT patients, 210 (44.3%; 95% CI 39.8-48.8) were performed for abnormal liver function tests during the study period. Majority of patients were Caucasian (83.8%), male (62.4%) with median age of 55 years (IQR 48-62 years). Biliary cannulation was successful in 99.6% of cases and findings included stricture in 45 (21.4 %); biliary stones/sludge in 23 (11%); biliary dilation alone in 31 (14.8%); and normal in 91 (43.3%). Three (1.4%) patients developed mild, self-limiting pancreatitis; one patient (0.5%) developed cholangitis and two (1%) had postsphincterotomy bleeding. Multivariate analyses showed significant association between dilated ducts on imaging with a therapeutic outcome. Conclusion. Diagnostic ERCP in OLT patients presenting with liver function test abnormalities is safe and frequently therapeutic.