Numerous studies, including the National Health and Nutrition Examination Survey, have suggested inadequate control in patients with hypertension. Few studies have investigated the factors that may contribute to inadequate blood pressure control. This study assesses adequacy of blood pressure control in patients treated at two osteopathic resident-training family practice centers and investigates potential barriers to adequate blood pressure control in this setting. The care of 127 hypertensive patients was studied for 9 months. The charts of these patients were examined for blood pressure readings, gender, number of missed visits, comorbid conditions, and changes in medications. The adequacy of blood pressure control was assessed by the standards promulgated by the sixth report of the Joint National Committee guidelines. Barriers to adequate control, including missed visits and changes in medications, were assessed. With the standard of control as a mean blood pressure of less than or equal to 140/80 mm Hg, 51.2% of the sample had controlled blood pressure. Factors that were associated with a significant reduction in the control of blood pressure were (1) patients new to the practice, (2) patients who missed follow-up visits for treatment of hypertension, and (3) patients who were undergoing changes in their medication profiles. Although rates of blood pressure control in this population are higher than those previously reported in the general population, they demonstrate room for improvement. Factors that are less under the control of physicians may be responsible for a large percentage of patients with uncontrolled hypertension. An understanding of the factors associated with poor blood pressure control is important in developing interventions to improve adequacy of blood pressure control.