Features of metabolic syndrome are not uncommon in patients after liver transplantation. To examine the prevalence and risk factors of posttransplantation metabolic syndrome (PTMS), the files of 252 transplant recipients (mean age, 54.5 ± 2.8 years, 57.9% male) were reviewed for pretransplant and posttransplant clinical and laboratory parameters (mean follow-up, 6.2 ± 4.4 years). Rates of obesity (body mass index >30 kg/m2), hypertriglyceridemia (>150 mg/dL), high-density lipoprotein cholesterol <40 mg/dL (men) or <50 mg/dL (women), hypertension, and diabetes were significantly higher after transplantation than before. Metabolic syndrome was diagnosed in 5.4% of patients before transplantation and 51.9% after. Besides significantly higher rates of the typical metabolic derangements (P < 0.0001), the patients with PTMS were older and heavier than those without PTMS, and they had a higher rate of pretransplant hepatitis C virus infection (P < 0.03) and more posttransplant major vascular and cardiac events (20 events in 15.2% of patients with PTMS versus 6 events in 4.9% of patients without PTMS; P < 0.007). There was no between-group difference in mortality or causes of death (mainly related to recurrent disease, graft failure, and sepsis). Significant independent predictors of PTMS on logistic regression analysis were age (odds ratio [OR] = 1.04), pretransplant nonalcoholic fatty liver disease (OR = 3.4), body mass index (OR = 1.13), diabetes (OR = 5.95), and triglycerides (OR = 1.01). The rate of metabolic syndrome in liver transplant recipients is more than twice that reported for the general population. PTMS is associated with cardiovascular morbidity but not mortality, and it may be predicted by pretransplantation conditions. Prospective studies are required to determine the significance and management of PTMS. Liver Transpl 17:15–22, 2011. © 2011 AASLD.