Objectives: To assess medication adherence, illness perception, beliefs about medications, to examine their association with blood pressure control among patients in Zagazig University hospital. Method: A cross-sectional study was held on 259 hypertensive patients attending Internal Medicine outpatient clinic, Zagazig University hospital. They underwent complete history taking, comprehensive clinical examination comprising assessing of their blood pressure. Then the patients completed Modified Morisky scale-8 (MMS-8), brief illness perception (BIPQ) and belief about medication (BMQ) questionnaires. Results: About 55% and 58% reported poor blood pressure control and medication adherence respectively. There is statistically significant relation between blood pressure control and patients’ sex, education, occupation, medication number, IPR causal domain, family history of hypertension-induced mortality, BIPR score, general overuse, specific necessity, specific concern, and adherence. There were significant relations between adherence and patients’ sex, social class, marital status, education, occupation, duration, medications number, family history of hypertension-induced mortality, IPQ causal item, general overuse, specific concern, and necessity. Significant risk factors of both poor control and medication adherence included specific necessity ≤ 9, general overuse >15 and using 3 to 4 drugs. Male, not working/unskilled increased risk of poor control. Not working/unskilled workers and skilled worker/free business, disease duration >5 years, perceiving lifestyle and hereditary as hypertension causes, having secondary education or higher were significant protectors from poor adherence. Conclusion: Belief about medications and illness perception were among the predictors of poor medication adherence and blood pressure control as well. Both can affect blood pressure control directly or indirectly via influencing adherence. Keywords: perception, beliefs, adherence