Objective To investigate the clinical characteristics and risk factors of multi-drug resistant (MDR) acinetobacter baumannii (Ab) infection in patients with sepsis in ICU.Methods Retrospectively analyzed clinical data of 856 cases of sepsis admitted in ICU of our hospital from July 2009 to March 2013,who were divided into MDR Ab related sepsis group (179 cases) and non-MDR Ab related sepsis group (control group,677 cases).Mortality rate,hospitalization expenses,organ function injury level and risk factors of death were compared between two groups.Results Mortality rate,48 hours mortality rate and hospitalization cost of MDR Ab related sepsis group were higher than those of control group (P ＜ 0.05).Septic shock,acute kidney injury and bone marrow suppression more likely occurred in MDR Ab related sepsis group (P ＜ 0.05).APACHE Ⅱ score ＞ 25,septic shock and multiple organ dysfunction syndrome (MODS) within 24 h were risk factors of death in MDR Ab related sepsis group (P ＜ 0.05).Conclusions Patients with MDR Ab related sepsis have worse prognosis and spend more in related treatment.It is important to detect risk factors of death and implement targeting treatment early.