We conducted a cross-sectional study to estimate the prevalence of metabolic syndrome, a clustering of risk factors associated with cardiovascular disease, among 86 adults who had allogeneic hematopoietic-cell transplant (HCT) as compared with 258 age- and gender-matched US population controls selected from the 2005-2006 National Health and Nutrition Examination Survey database. The median age at study enrollment was 50 years (range, 21-71), and patients were at a median of 3 years (range, 1-21) from HCT. The prevalence of metabolic syndrome was 49% (95% confidence intervals (CI), 38-60%) among HCT recipients, a 2.2-fold (95% CI, 1.3-3.6, P=0.002) increase compared with controls. The prevalence rates of elevated blood pressure and hypertriglyceridemia were significantly higher among HCT recipients than among controls, but the prevalence rates of abdominal obesity, elevated blood glucose and low high-density lipoprotein cholesterol were not. HCT survivors with metabolic syndrome were more likely to have microalbuminuria (43 vs 10%) and elevated creatinine (31 vs 11%). No patient, donor or transplant characteristics were associated with the diagnosis of metabolic syndrome. We conclude that metabolic syndrome occurs frequently among allogeneic HCT survivors who are seen by transplant physicians. Approaches to screening, prevention and management of metabolic syndrome should be developed for HCT recipients.