The manner in which executive control functioning exerts its influence on functional tasks was investigated. Sixty older adults were administered neuropsychological tasks tapping into four domains of executive control function, including working memory, planning, fluency, and flexibility. A test of performance-based functional ability also was administered. Correlational analyses demonstrated that working memory was most strongly associated with performance-based functional ability; however, impairment in planning appeared to best predict performance-based functional decrement in simultaneous regression models. Results highlight the role of planning in the maintenance of functional ability, as measured by performance-based functional measures.