Background and Aim: Liver transplantation (LT) is a lifesaving procedure for patients with end-stage liver disease when there is no available medical or surgical treatment. Biliary complications after liver transplantation remain a major source of morbidity and mortality. So our aim was to focus on and analyze this complication in a large tertiary referral academic liver transplantation center. Patients and Methods: Between the years 2005 and 2006 a final cohort of 179 adult patients (102 males, average age 49 years) received primary LT (mainly due to viral hepatitis, alcoholic liver disease, hepato-cellular carcinoma “HCC” and primary sclerosing cholangitis “PSC”) in the LT center of Hannover Medical School, Hannover/Germany was prospectively followed-up till end of 2009. The cohort was divided into two groups: Group A (n=121) includes patients who did not develop biliary complications and Group B (n=58) representing the biliary complications group. Comparison between the two groups in all the collected peri- and post LT parameters was achieved.Results: Thirty two percent of the patients developed 89 different biliary complications. Biliary strictures were the leading complication (57.3%) followed by biliary stones/casts (24.7%) then biliary leak (16.9%) and finally sphincter of Oddi dysfunction “SOD” (1.1%). Risk factors and consequences of biliary tract complications post LT: Recipient BMI (p=0.023), LT due to viral hepatitis (p=0.042) or autoimmune hepatitis “AIH” (p=0.008), LT in CHILD C stage (p=0.008), ascites pre LT (p=0.001), hepatic encephalopathy pre LT (p=0.024), dialysis pre LT (p=0.022), lower serum albumin pre LT (p=0.046), lower serum choline esterase pre LT (p=0.026), lower platelet count pre LT (p=0.013), longer cold ischemia time “CIT” (p=0.006), longer operation time (p=0.035). LT due to PSC (p=0.025) or in CHILD A stage (p=0.012) was protective. Multi-variate analysis of significant risk factors revealed that LT due to AIH, ascites pre LT, renal dialysis pre LT, longer CIT and longer operation time are all independent risk factors. The development of biliary complications is associated with significantly shorter all over survival (p=0.029), one-year survival (p=0.028) and the two-year survival (p=0.022) post LT. Subsequently, higher mortality rate (p=0.012) was detected in comparison with the patients who did not suffer from biliary complications. Risk factors for development of ischemic type biliary lesion “ITBL” post LT: The data of the subgroup of patients who developed ITBL and survived longer than three months (n=21) were compared to the data of the corresponding patients who did not develop any biliary complication and survived also at least for three months (n=104) resulting in the following risk factors: older donors (56 vs. 46 years, p=0.005), ascites pre LT (76.2% vs. 48.1%, p=0.019), encephalopathy pre LT (42.9% vs. 20.2%, p=0.027), renal dialysis pre LT (14.3% vs. 1.9%, p=0.008), higher pre LT serum Creatinine (p=0.019), longer CIT (734 vs. 630 min, p=0.025), renal dialysis post LT (38.1% vs. 18.3%, p=0.044), CMV hepatitis post LT (23.8% vs. 6.7%, p=0.015). The development of ITBL significantly shortened the patient’s survival (912 vs. 1309 days, p=0.005) and graft survival so that significantly more re LT was required (9.5% vs. 1%, p=0.019) than the complication-free group; hence the higher mortality (42.9% vs. 14.4% respectively, p=0.003) within the ITBL group. Comparison between AS and ITBL: After exclusion of two patients from the AS group (they developed ITBL strictures in follow up), the peri-transplant and management data of the remaining 25 patients were compared to the corresponding data of the 22 patients in the ITBL group who had: older donors (56.5 vs. 47 years, p=0.024), higher serum Creatinine pre LT (p=0.034), less split liver grafts (20% vs. 0%, p=0.026) and less recurrence post LT (40% vs. 13.6%, p=0.044).Cholangiographic intervention, mainly ERCP, was the main diagnostic/therapeutic tool advocated in the management (93%), whereas the surgical repair or reconstruction biliary system (7%) was preserved for the severe complications or whenever endoscopic/percutaneous route failed. ERCP presentations (n=243) for all patients were associated with minor post-procedural complications mainly cholangitis (5.8%), pancreatitis (2.5%) and bleeding (1.6%); there were no cases with perforation and all complications were treated conservatively with no need for surgical management. After all PTCD procedures (n=29) only one complication (3.4%) occurred in form of dislocation of the drainage and pleural fistula and was treated with removal of the drainage and antibiotics. Microbiological analysis of bile: From the 88 bile samples collected via ERCP, 85 (96.6%) samples showed positive bacterial growth and only three (3.4%) samples were sterile. In the positive cultures, a total of 229 organisms representing 53 different species were identified. Gram positive organisms represented the majority of the positive growths (48%), mainly Enterococcus spp. and Streptococcus spp., followed by gram negative organisms (29.3%), mainly E. coli and Klebsiella spp., then fungal growths (14.4%), mainly Candida spp. and finally anaerobes (8.3%), mainly Clostridium perfringens. Conclusion: biliary complications (especially ITBL) are still major source of morbidity after LT affecting more than one third of the recipients and significantly shorten the patient and graft survival. The more advanced the hepato-renal condition prior LT, the more the risk to develop biliary complications post LT. ERCP is successful in the management of these complications with rare post interventional complications. Positive bacterial growth (especially gram positive organisms) in bile was detected in almost all patients represented for the management of the biliary complications.