Infection is a common cause of morbidity and mortality after liver transplantation, which are often caused by Gram negative bacteria and the most frequently occurring infectious complications after liver transplantation (LT). The aim of this study was to investigate, incidence, pathogenic spectrum, and risk factors for bacteria due to multidrug resistant (MDR) Gram-negative bacteria, and its impact on mortality after LT. In total, 150 consecutive patients who underwent liver transplantation between January 2012 and March 2013, 115 isolates of bacteria and 10 isolates fungal from 80 patients. MicroScan® microbiology and API20 were used to identify the all isolates. Bacterial infections represented the most frequent event (92.0%) and fungal infections (8.0%). The presumed sources of infection were the Urine (41 events, 51%), followed by the bail drain (14 events, 17.5%). Infections of the sputum, ascetic fluid, and blood site accounted for 13.8, 5.0 and 6.3%, respectively. Antibiotics the most susceptible antibiotic against Pseudomonas aeruginosa was colistin (94.1%). Patients with Gramnegative bacilli after liver transplantation show a significantly worse prognosis. Gram-negative bacteria after liver transplantation have been a major problem in our center.