Regression analyses using Blood Pressure, Age, and the multiplicative effect of Blood Pressure and Age as predictors of performance (on selected tests from the Halstead-Reitan neuropsychological test battery) were done. Three hypotheses were tested with subjects ranging in age from 20 to 72 years of age: (1) blood pressure values predict neuropsychological test performance over a wide range of hypertensive and normotensive blood pressure values; (2) blood pressure predicts performance within the narrower range of normal and borderline values; (3) blood pressure X age interactions, when observed over this age and education range, are such that negative blood pressure effects on performance are larger for younger than older subjects. Regression analyses confirmed each of these hypotheses and indicated that strength of prediction was not reduced when participants free from hypertension-related complications and medication were tested. Blood pressure X age interactions were seen for Trailmaking-B Test and the Tactile Performance Test-Localization for the primary sample. However, only Blood Pressure main effects were observed for the Average Impairment Rating, the Categories Test, TPT-Memory and TPT-Localization when age, sex, and education were controlled. Implications of these findings for the role of blood pressure in aging research and for longitudinal studies with subjects free from the need for treatment with antihypertensive medications are discussed.