A growth curve analysis was used to examine estimated longitudinal decline (over 19 years) on the Wechsler Adult Intelligence Scale (WAIS; D. Wechsler, 1955) in relation to arterial hypertension and blood pressure (BP) for 55 men and 85 women (40 to 70 years old) who were free from overt major coexisting diseases. BP was associated with longitudinal decline for Visualization-Performance (VP) ability and Speed. Hypertension was a weaker predictor of VP and was unrelated to Speed. Age effects on VP were overestimated when averaged BP level, particularly systolic BP, was not controlled statistically. It was concluded that initial BP level and hypertension predict age-related longitudinal decline in specific major abilities assessed by the WAIS but that BP averaged over examinations is a stronger predictor.