We examined the workload implications of the National Service Framework for Coronary Heart Disease and the 1999 British Hypertension Society guidelines for the management of hypertension in clinical practice. The 1998 Health Survey for England was used to estimate the proportion of the English population aged 35 to 74 years that may require antihypertensive therapy. Of 8,154 subjects with blood pressure measurements, 400 (4.9%; 95% CI 4.4 to 5.4%) with cardiovascular disease were taking antihypertensive drugs and a further 100 (1.2%; 1.0 to 1.5%) were at treatment thresholds for secondary prevention of cardiovascular disease. There were 848 (10.4%; 9.7 to 11.1%) subjects free of cardiovascular disease on antihypertensive therapy and an additional 1,083 (13.3%; 12.5 to 14.0%) were identified for treatment. We estimate that 29.8% (28.8 to 30.8%) of the English population aged 35 to 74 years were candidates for antihypertensive therapy, of which 15.3% (14.5 to 16.1%) were already being treated but only 5.4% (4.9 to 5.9%) had their blood pressure controlled. An additional 14.5% of the English population will need antihypertensive therapy and an extra 9.9% will need to have their treatment intensified to attain the blood pressure targets set by the British Hypertension Society guidelines.