Purpose: The aim of this paper is to determine the association between the knowledge of hypertension management and drug adherence for patients with Hypertension in Saudi Arabia. Method: The research involves a cross-sectional study in which 198 high-blood pressure patients from several (27) hospitals in seven Saudi Arabian cities: Riyadh, Dammam, Alahsa, Alqatif, Makkah, Jeddah, and Taif, were surveyed. A questionnaire, which was divided into three sections – demographic data, hypertension knowledge questions, and medication adherence, was used to collect data on how aware are the patients of managing hypertension. Descriptive statistics were utilized to determine patient’s demographic attributes and Spearman rank correlation was used to evaluate the relationship between disease familiarity and medication adherence. Results: Out of the 198 patients surveyed, about 58.08% (115 patients) were within the poor knowledge category; while, 132 (66.67%) were categorized as moderate adherent to medication. Only 15 (7.58%) patients were considered as being good adherents to hypertensive medication. The correlation coefficient between overall score of knowledge and that of medication adherence was -0.1889 (ρ<0.001), suggesting a converse relationship between overall knowledge cores and the level of medication adherence. Conclusion: While the scores of knowledge were overall poor, the patients were not sure of the benefits associated with continuous use of medication which leads to non-adherence to treatment regimens. Enlightening patients regarding the importance and associate gains of hypertensive medication and expounding on any doubts with regards to the use of drugs should lead to better treatment and management of hypertension.