Cardiac and cerebral vascular diseases are leading causes of morbidity and death in solid organ transplant recipients. Immunosuppressant drugs are associated with dyslipidemia, hypertension, and hyperglycemia, which along with obesity are the main features of metabolic syndrome. In the nontransplant population, metabolic syndrome is associated with increased risk for major vascular complications. We postulated that metabolic syndrome is common post-liver transplantation and plays a significant role leading to cardiac and cerebrovascular events. Our Multi-Organ Transplant Program database was reviewed for all liver transplant recipients between January 1998 and June 2004 with follow-up until December 2005. We adapted the 2001 National Cholesterol Education Program-Adult Treatment Panel III Guidelines to define posttransplantation metabolic syndrome (PTMS) as the presence at least 3 of the following: 1) obesity (body mass index>30 kg/m2); 2) serum triglyceride level>or=1.7 mmol/L; 3) high density lipoprotein level<1 mmol/L in men and <1.3 mmol/L in women; 4) hypertension; and 5) fasting plasma glucose>or=5.6 mmol/L. A total of 118 patients were included. Among them, 69 patients (58%) had PTMS. The mean (+/-standard deviation) time from transplant was 59+/-21 months (no significant difference in patients with or without metabolic syndrome). Overall, patients with metabolic syndrome had a significantly higher average age, posttransplantation body mass index, fasting glucose, high-density lipoprotein levels, and serum triglycerides. There was no difference in creatinine, hemoglobin, or prednisone average dose between the 2 groups. There were 25 major vascular events affecting 21% of patients. There were significantly more vascular events in patients with metabolic syndrome posttransplantation than in those without (30% vs. 8%; P=0.003) during the study period. In conclusion, the prevalence of metabolic syndrome post-liver transplant is significantly higher than that estimated in the general population. Metabolic syndrome appears to be associated with an increased risk of major vascular events in our liver transplant population.