Hypertension affects 25 % of the adult US population overall and remains a leading cause of cardiovascular disease. Only 25 % of people with hypertension are at goal blood pressure (BP). The Hypertension Improvement Project (HIP) is a randomized, controlled trial that will test the separate and combined effects on BP control of a continuous quality improvement (CQI) intervention for physicians and a behavioral intervention for patients. Physicians will be selected from practices in the Duke Primary Care Research Consortium that serve low income and minority populations. Practices are randomly assigned to the physician (MD) intervention or to the MD control condition. Within these practices, all MDs receive the same intervention, and their patients are individually randomized to the patient intervention or to the patient usual care condition. The MD intervention consists of three main elements: on-line training modules; an evaluation and treatment algorithm for use in the clinic; and a CQI procedure involving assessment of Clinical Performance Measures and feedback to physicians on their adherence to guidelines. The performance data will be collected for 18 months and feedback will be provided to MDs every 3 months. Patients from these practices (approximately 50% women, at least 40% African American, 90% low income) will be randomly assigned to the patient intervention or usual care. The patient intervention consists of a 6-month behavioral intervention aimed at lifestyle changes to lower BP and adherence to prescribed BP medications. BP and other follow-up measurements are performed at the end of the intervention and a year later (i.e., at 6 and 18 months postrandomization). The primary outcome is the proportion of patients in each treatment group that have adequate BP control at 6 months. BP control is defined by JNC-6 goals (systolic BP < 140 and diastolic BP < 90 mmHg for most patients; lower goals for patients with cardiovascular or renal disease or diabetes). Other outcomes include BP control at 18 months, physician adherence to national guidelines, and patient adherence to lifestyle recommendations and medication regimens. A cost analysis will also be done. The study will enroll 400 patients in 10 practices (approximately 20 physicians), and will have 80% power to detect an effect size of 0.3 for the primary outcome. The HIP study will test practical interventions for improving hypertension control that can be broadly implemented and reduce CVD risk.