BACKGROUND Most liver transplant patients require Intensive Care Unit (ICU) care in the immediate postoperative period and some patients require readmission to the ICU before discharge from the hospital. A retrospective cohort study was conducted to identify risk factors for ICU readmission after liver transplantation. MATERIAL AND METHODS Adult patients who underwent living donor or deceased donor liver transplantation at Seoul National University Hospital between 2004 and 2015 were included. A retrospective review of baseline and perioperative factors that may be associated with ICU readmission was performed. Patients requiring ICU readmission during the hospitalization for LT (readmission group) were compared with patients who did not need ICU readmission (control group). A multivariable logistic regression analysis was performed to identify factors associated with ICU readmission after LT. RESULTS Of the 1181 patients, 68 patients (5.8%) were readmitted to the ICU during the postoperative period after liver transplantation. Common causes of ICU readmission included postoperative bleeding, pulmonary complications, and sepsis. Multivariate analysis revealed that old age (OR 1.030 95%CI 1.002-1.059, p=0.035), pre-transplant chronic kidney disease (CKD) (OR 4.912 95%CI 2.556-9.439, p<0.001), intraoperative red blood cell (RBC) transfusion (OR 1.029 95%CI 1.008-1.050, p=0.007), new-onset atrial fibrillation in the ICU (OR 2.807 95%CI 1.087-7.249, p=0.033), and transplantation between 2011 and 2015 (vs. 2004-2010) were risk factors for ICU readmission after LT. CONCLUSIONS Old age, pre-transplant CKD, more intraoperative RBC transfusion, new-onset atrial fibrillation during ICU stay, and transplant period were identified as risk factors for ICU readmission.