Poor adherence to drug therapy decreases the effectiveness of antihypertensive treatment. Patients must take more than 80% of their antihypertensive drugs to maintain adequate blood pressure control. To understand the incidence of noncompliance and contributing factors, a pilot study was conducted in which a questionnaire was devised and administered to a random sample of 243 hypertensive patients of the adult ambulatory care clinic at Methodist Hospital of Indiana. Ninety-eight patients completed the telephone survey. Demographic data were obtained through chart reviews. The results indicated that 30-46% of the patients were noncompliant with their antihypertensive drug regimens. Factors found to be associated with noncompliance were; employment (P = .0077), use of home remedies (P = .0043), age (P = .0165), experience of side effects (P = .0051), level of concern with missed doses (P = .0043), and cost (P = .014). The incidence of noncompliance in this pilot sample is lower than the estimated 50% noncompliance rate of published data. More research is needed to understand the determinants of noncompliance in order to design interventions to improve compliance.