BACKGROUND: While there have been epidemiologic studies of blood donors, the characteristics of individuals who receive transfusions have not been well described for the US population. STUDY DESIGN AND METHODS: Subjects were from the nationally representative Health and Retirement Study whose data were linked to Medicare files from 1991 through 2007 (n = 16,377). A cohort study was conducted to assess the frequency of transfusion in older Americans over time and to describe the characteristics of blood recipients. RESULTS: Thirty-one percent (95% confidence interval [CI], 30%-33%) of older Americans received at least one transfusion within a 10-year period and 5.8% (95% CI, 5.4%-6.2%) experienced repeated transfusion-related visits within 30 days. The mean number of transfusion-related visits was 2.3 over a 10-year period (95% CI, 2.2-2.4). Older Americans who lived in the South were most likely to receive a transfusion (34%), independent of demographic and health-related factors, while those who lived in the western United States were the least likely (26%). Predictors of transfusion included smoking, low body mass index, and a history of cancer, diabetes mellitus, end-stage renal disease, and heart disease. African-Americans and Mexican-Americans had greater rates of blood utilization than other races and other Hispanics (respectively). There were also differences in transfusion utilization by education, marital status, religion, and alcohol use. CONCLUSIONS: Transfusion is common in older Americans. Regional variations in blood use are not explained by patient characteristics alone.