The study dealt with the hypertensive patients' treatment compliance in the selected municipalities in the First District of Ilocos Sur for the Calendar Year 2020. It described the respondents’ treatment compliance on hypertensive medication, follow-up check-up, and lifestyle modification. It also identified the perceived barriers in taking the medication. Lastly, it looked into the significant relationship between the respondents' treatment compliance and their profile, perceived causes, and knowledge of hypertension. The study used the descriptive-correlational method. All the 209 hypertensive patients who sought consultation at the Municipal Health Offies (MHOs) of Caoayan, Vigan , and Sto. Domingo for July and August 2020 served as the respondents. The data were collected using a questionnaire-checklist formulated by the researchers and content validated by a pool of experts. Data were treated through frequency and percentage, mean, and simple linear correlation analysis. A great majority of the respondents are married and with a family history of hypertension. The majority are females and have no family history of cardiovascular disease. A significant percentage are 55-59 years old, high school graduates, unskilled workers, earn monthly of Php 5,000 and below, and have Stage 2 hypertension. Eating of high cholesterol foods was perceived as the number one cause of hypertension. Almost all of the respondents know that hypertension is preventable, curable, fatal, and can lead to a heart attack or stroke complications that are preventable. A person on treatment cannot stop medication after normalizing blood pressure. The respondents’ overall treatment compliance is “Very High,” and they “Moderately Agree” on the cost, symptom experience, work-related, availability/ accessibility, family-related, and personal-related matters as barriers in taking the hypertensive medications. The family monthly income, cardiovascular disease presence, perceived causes, and knowledge of hypertension are significantly related to treatment compliance.