Research has shown sex differences in performance favoring males are likely to be reported on cognitive tasks requiring spatial skills. It has also been suggested that the reason why individuals who describe themselves as masculine also tend to do well on spatial tasks may be a function of activity preference. To examine the relationship among college students' spatial performance, spatial activity preferences, and self-descriptions, college men (N=144) and college women (N=191) were tested in three studies on one of two spatial tasks, and surveyed on their participation in 81 space-related activities. In all three studies, better spatial performance was associated with higher self-reports of participation in masculine, but not feminine, spatial activities. In the second and third studies, participants also took the Bem Sex-Role Inventory. Women and men who were masculine did better on the spatial tasks than did women and men who were feminine. Results suggest that even small differences in activity preferences may help explain the commonly observed sex differences on spatial tasks. (Author/JAC)