To assess the quality of the pharmacological control of hypertension. A cross-sectional study. Primary health care centers-registered hypertensive patients. Primary health care centers in Al-Khobar, Saudi Arabia. Data was recorded, using a structured questionnaire, through direct interviewing of patients, and from their medical records. It included demographic characteristics, hypertension related, and doctors'-related variables; and patients' utilization of other health facilities and whether they had other chronic diseases. The proportion of patients with controlled hypertension was 37%. It was significantly increased with age below 55 years, with non-Saudis, duration of treatment shorter than 5 years; and with the use of monotherapy. Doctors' care-related variables did not show significant variation with the number of controlled patients which may imply that the quality of follow-up might not be adequate. The proportion of controlled patients cared for in the PHC centers is low. The factors associated with control were age, and the use of a single antihypertensive drug. The study questions the quality of follow-up of patients by the PHC physicians.