The present study tested sequential difficulty effects (SDEs) in arithmetic problem solving and Fitts’ aiming task for the same individuals. SDEs refer to poorer performance on current items following harder items relative to after easier items. Young and older adults accomplished an arithmetic task (i.e., finding the approximate products to two-digit multiplication problems) and a Fitts aiming task (i.e., performing rapid pointing movements to reach the finish areas). Current items were preceded by two easy or difficult items (i.e., in the repeated-precursor condition) or only one easy or difficult item (i.e., in the unrepeated-precursor condition). Participants’ performance revealed SDEs in both the arithmetic and the aiming tasks only when the difficulty level of the precursor items was repeated. Data also revealed comparable SDEs in both age groups during the arithmetic task but SDEs only in older adults while participants accomplished the aiming task. These findings have a number of implications for our understanding of mechanisms underlying SDEs and age-related differences in SDEs, as they suggest that SDEs involve both domain-general and domain-specific mechanisms that are differentially influenced by aging.