Trends in blood pressure prevalence and control have important public health implications. We aim to document trends in hypertension prevalence, awareness and control in the older Australian population, a group at greatest risk of blood pressure related diseases. The Blue Mountains Eye Study (BMES) is a population-based study of residents aged 49 years or older, in two postcode areas of the Blue Mountains, Australia. The first cross-section (BMES I, 1992-1994) included 3654 participants (82.4% of eligible). The second cross-section (BMES II, 1997-2000) included 3509 participants, 2335 (75.1% of BMES I survivors) and 1174 (85.2% of newly eligible residents who qualified because of age or moved into the area). Detailed history and examinations were conducted. The prevalence of hypertension increased significantly from 45.4% (95% confidence interval, CI 43.7-47.0%) to 52.2% (CI 50.6-53.9%) from 1992-1994 to 1997-2000, paralleled by an increase in the population mean body mass index (BMI) from 26.1 kg/m2 (CI 26.0-26.3 kg/m2) to 27.7 kg/m2 (CI 27.5-27.9 kg/m2). Hypertension awareness decreased significantly from 79.8 to 73.0%, while treatment and control rates decreased from 71.1 to 67.3% and 56.3 to 46.5%, respectively (P<0.0001). Our results showed that elevated BMI (P<0.0001), lack of exercise (P<0.002) and serum triglyceride >2 mmol/l (P<0.0001) were significantly associated with prevalence of hypertension. We found that the prevalence of hypertension in the older Australian population was increasing while awareness, treatment and control rates decreased. Programmes to improve community awareness of hypertension, and its association with BMI may lead to further reductions in blood pressure and the burden of cardiovascular disease.