Introduction: Hypertension prevalence is increasing globally and has become a major issue of disease as it is a major cause for cerebrovascular, kidney and cardiovascular diseases. Even among treated patients, there is a dispropor-tional of blood pressure control causing a major public health challenge. This study is aimed to decide on the prev-alence of uncontrolled hypertension and its associated factors among hypertensive patient attending hypertension clinic at primary health clinics in Tuaran district. This study is justified by the fact that uncontrolled hypertension leads to high mortality, morbidity and even premature death. Methods: This study is a cross-sectional study among 460 hypertensive patients attending three primary health clinics in Tuaran district, Sabah. Data were collected using structured modified questionnaires through interviews, physical examinations and patient’s medical records. Types of data collected include socio-demography, lifestyle behavior, physical examination, co-morbidity status and med-ical adherence. Data analysis done using SPSS version 24.0. Results: Prevalence of uncontrolled hypertension was 45.9%. The study found that factors significantly associated with uncontrolled hypertension with p