To describe hypertension trends in US adults aged 65 years and older using Medicare Current Beneficiary Survey (MCBS) data, a cross-sectional, nationally representative health examination survey from MCBS files between 1999 and 2004 was investigated. Overall, 62% of beneficiaries, or an estimated 20 million US adults aged 65 years and older, were hypertensive as extrapolated from MCBS data. From 1999 to 2004, the prevalence rate of hypertension increased from 59% to 65% (P<.001). Nonwhite persons and women had a higher prevalence of hypertension than whites and men. A history of diabetes mellitus, prior myocardial infarction, coronary artery disease, or stroke was significantly associated with hypertension treatment. In addition, significant geographic variation in treatment was noted. There was a significant increase in hypertension prevalence in older Medicare beneficiaries from 1999 to 2004. Women, patients 85 years and older, and nonwhite patients were less likely to be treated with antihypertensive medications, and significant geographic variation existed in treatment.