The authors analyzed data on 9950 participants taking antihypertensive medications in the nationwide Reasons for Geographic and Racial Differences in Stroke (REGARDS) study to determine the association between medication adherence and incident stroke symptoms. Medication adherence was assessed using a validated 4-item self-report scale and participants were categorized into 4 groups (scores of 0, 1, 2, and 3 or 4, with higher scores indicating worse adherence). The incidence of 6 stroke symptoms (sudden weakness on one side of the body, numbness, painless loss of vision in one or both eyes, loss of half vision, losing the ability to understand people, and losing the ability to express oneself verbally or in writing) was assessed via telephone interviews every 6months. During a median of 4years, the incidence of any stroke symptom was 14.6%, 17.9%, 20.2%, and 24.9% among participants with adherence scores of 0, 1, 2, and 3 or 4, respectively (P<.001). The multivariable adjusted hazard ratio (95% confidence interval) for any stroke symptom associated with adherence scores of 1, 2, and 3 or 4, vs 0, was 1.20 (1.04-1.39), 1.23 (0.94-1.60), and 1.59 (1.08-2.33), respectively (P<.001). Worse adherence was also associated with higher multivariable adjusted hazard ratios for each of the 6 stroke symptoms. © 2011 Wiley Periodicals, Inc.