Gender differences in spatial ability in old age were examined longitudinally and the effectiveness of cognitive training in reducing these differences was assessed. The mental rotation ability of older participants (N=229; M age=72.8 years) from the Seattle Longitudinal Study was examined over a 14-year period (1970–1984) from late middle age into old age. Both men and women exhibited normative age-related decline in spatial ability performance across the 14-year period; the magnitude of the gender difference remained constant across this period of decline. A significantly greater proportion of the age-related decline was associated with a drop in speed of problem solving for men than for women. Following training on mental rotation ability, there was no significant gender difference in spatial ability performance. Women exhibited significantly greater pretest-posttest gains, on average, than did men. A greater proportion of training improvement for women compared to men was attributable to increased accuracy. Training was particularly effective for older women who had experienced prior age-related decline.