This study aimed to estimate the prevalence of uncontrolled hypertension (HTN) among Omani hypertensive patients, on treatment and under primary health care (PHC) follow-up in Al Seeb Wilayat, Oman. Socio-demographic and clinical factors were explored for possible influence on blood pressure (BP) control. Methods: Based on an assumption of 50% prevalence of uncontrolled HTN, a retrospective data collection was conducted on the last three follow-up visits of 411 randomly selected Omani adults (≥18 years) from 3,459 hypertensive patients. Adequate BP control was defined using criteria from 7th Report of the Joint National Committee on Prevention Detection Evaluation & Treatment of High Blood Pressure (JNC-7). A P value of <0.05 and odds ratios with 95% confidence interval were used to assess for association. Results: The targets for adequate BP control were achieved in 39% of the studied patients (95% confidence interval [CI]: 34–44%). Lower BP control was found among hypertensives with diabetes (6.4%, P = <0.001) and renal disease (18.5%, P = 0.02); those with cardiovascular disease (CVD) showed relatively better control (58%). Age and gender had no impact on BP control. Most patients were only on one (24%) or two (47%) antihypertensive medications, the most frequently used being β-blockers (58.2%) and diuretics (56.3%). Conclusion: HTN is not adequately controlled in over 60% of treated patients; the presence of co-morbidity and less than aggressive treatment are significant contributors. Improving the quality of HTN care is a priority; effective efforts should be undertaken to improve BP control.