This prospective study tested interventions directed at 32 physicians and 574 patients over an 18-month time period aiming at lowering blood pressure. The physician interventions included Internet-base learning, self-monitoring, and quarterly feedback reports. For the patients, the intervention included 20 weekly group sessions over 6 months, followed by 12 monthly telephone counseling contacts. The Hypertension improvement project (HIP) trial showed that the main effect of the patient intervention was -2.6 mm Hg (95% CI: -4.4 to -0.7; p=0.01) which was explained by the adoption of a healthy dietary pattern and weight loss. The intervention for the physician alone did not lead to better blood pressure management. The key finding of the trial was that the largest impact on blood pressure was observed with the combination of both interventions. However, difference between treatment groups did not persist at 18 months.