To examine the effects of cognitive task demands on manual asymmetry, 40 male and 40 female college students were asked to simultaneously construct two replicas of a verbal or spatial block design task, one with each hand. In addition, a verbal and spatial competition task also was performed concurrently with each of the two primary tasks in a dual task paradigm. The spatial primary task elicited increased left-hand use relative to baseline performance, but only in males. An increase in right-hand use was observed during performance of the verbal primary task, again primarily among males. The effects of concurrent cognitive tasks on hand utilization were observed only in subjects performing the verbal primary task, and only when the concurrent task was verbal in nature. Implications for theories of functional cerebral lateralization are discussed.