The goal of this study is to investigate the way of adherence to drug regime based on extended parallel process model in patients with hypertension referred to hospitals affiliated with the Islamic Azad University of medical sciences branch. This study was the kind of descriptive and correlational study that was conducted in medical clinics of heart of hospitals affiliated with the Medical Azad University of medical sciences branch of Tehran. In this study, participants were all patients with hypertension of 140.90 and higher that at least 6 months has passed of their disease duration of hypertension and they were treated with blood pressure medicines, and reffer to clinic of hospitals affiliated with Islamic Azad University of Tehran Medical Branch in order to control and track their blood pressure. Data were collected by using standard questionnaires. The frequency distribution of patients with hypertension to questions for fear of disease showed that 56.6 percent of agree opinion forms the highest rate. Also the average of total questions related to the fear structure was 16.3 with a standard deviation of 3.11. Frequency distribution in terms of answer to the questions of perceived susceptibility showed that 64.2 percent of agrees opinion contains the highest rate. Average number of total questions related to perceived susceptibility was also 17.22 with a standard deviation of 4.72. Fear of disease, perceived susceptibility toward disease plays a significant relationship with adherence to drug orders in patients with blood pressure. Adherence to incidence of hypertension, blood pressure control has great importance to make minimum the chance of incidence the complications due to high blood pressure.