Introduction:There are multiple factors that intervene in the lack of control of arterial hypertension such as adherence to antihypertensive treatment. Objectives:To find the frequency of adherence to antihypertensive treatment, to describe the level of knowledge about arterial hypertension and to determine the factors associated with the lack of blood pressure control.Methodology: An observational, prospective, multicenter study was carried out in men and women, of legal age, with arterial hypertension, from the area of influence of three Family Health Units in Paraguay between May-November 2019. Adherence to the antihypertensive treatment was determined with the ARMS-e questionnaire and the level of knowledge about arterial hypertension with the questionnaire by Strelec et al. Ethical standards were respected.Results: 171 subjects entered the study, with a mean age 59 ± 11 years, predominantly female (68%). The most frequent nutritional status was grade 1 obesity (35%). Diabetes mellitus was the predominant comorbidity (18%). The most commonly used drugs were angiotensin 1 inhibitors (56%). Adherence to antihypertensive treatment was detected in 116 cases (68%) and knowledge about arterial hypertension in 141 (82%). Uncontrolled blood pressure was found in 83 subjects (49%) and was significantly associated with lack of adherence to antihypertensive drugs and dependence on a caregiver within the family. Conclusions:The frequency of adherence to antihypertensive treatment in adult patients from 3 Family Health Units in Paraguay in 2019 was 68% and the adequate level of knowledge about arterial hypertension was 82%.