Background: Uncontrolled hypertension is one of the preventable causes of morbidity and mortality in worldwide. The burden of uncontrolled hypertension is on the increasing in developing countries and poorly addressed public health problems on its magnitude and its associated factors in Bensa district as well as the Sidama region. Objective: The aim of this study was to determine the magnitude of uncontrolled hypertension and its associated factors among hypertensive patients on treatment follow-up at public health facilities in Bensa district, Sidama region, Ethiopia, 2022. Methods: Cross-sectional study was conducted at public health facilities in Bensa district, Sidama region, Ethiopia from Mar 1/2022 to Apr 30/2022. Purposive sampling method was used to select public health facilities and simple random sampling method was used to select participants. Respondents were interviewed and their medical charts were reviewed using pretested structured questionnaire. Bivariable logistic regression was done to identify candidate predictors for uncontrolled blood pressure. Independent variables which had an association with the outcome variable at P-value <= 0.25 in the bivariable regression analysis was entered in the multivariable logistic regression model. The magnitude of association between independent and dependent variables was measured using odds ratios and 95% of confidence interval (CI) with a significant level (P-value< 0.05). Results: of the total 393 hypertensive patients were included in the study. The magnitude of uncontrolled hypertension was found to be 62% (95% CI: 57-67). Age ≥50 years old (AOR=2.7, 95% CI: 1.6-4.5), non-adherent to medication (AOR=2, 95% CI: 1.3-3.14), non-adherent to dietary (AOR=1.7, 95% CI: 1.06-2.86) and non-adherent to physical activity (AOR=1.8, 95% CI: 1.04-3.08) were significantly associated with uncontrolled hypertension Conclusion: Advanced age, non-adherent to their medications, non-adherent to dietary, and physical inactivity, were more likely to have uncontrolled hypertension. Therefore, increasing adherence to medication and diet, promoting physical activities and immediate attention of health professionals, administrations of district health office and regional health beuarue to control high blood pressure among hypertensive patients on treatment.