BACKGROUND: More than half of hypertensive patients reviewed at Lupane District Hospital during the first half of 2011 had uncontrolled hypertension. This prompted an investigation on the prevalence of uncontrolled hypertension and associated factors among hypertensives on treatment. METHODS: Analytical cross-sectional study was conducted. Three hundred fifty-four consenting participants were consecutively selected from eligible hypertensive patients on treatment attending the outpatients department at Lupane District Hospital for their reviews. An interviewer administered questionnaire adapted from the World Health Organization was used to collect data on risk factors. Blood pressure and anthropometric measurements were taken as per World Health Organization guidelines. Uncontrolled hypertension was defined as systolic blood pressure of ≥140 mmHg and/or diastolic blood pressure of ≥90 mmHg in a patient taking anti-hypertensive medication. RESULTS: Mean systolic BP was 151.0 mmHg and mean diastolic BP was 92.6 mmHg. Prevalence of uncontrolled hypertension was (238) 67.2%. Independent risk factors for uncontrolled hypertension were obesity (AOR 3.28, 95% CI 1.39-7.75) and adding salt to food at the table (AOR 2.77, 95% CI 1.41-5.43) whilst being compliant with the drug treatment regimen (AOR 0.34, 95% CI 0.16-0.72) and having received health education on hypertension (AOR 0.49, 95% CI 0.25- 0.97) were protective against uncontrolled hypertension. CONCLUSION: There prevalence of uncontrolled hypertension is high despite all the participants being on treatment. The findings suggest that interventions at the patient, the provider and the health delivery system are needed to improve hypertension control in Lupane, Zimbabwe.