The abilities of males and females to make spatial inferences were compared. Spatial inference is concerned with the ability to work out new spatial information from memory. In two experiments, participants had to study line drawings depicting shapes linked either by straight or meandering lines. Afterwards, they had to remember the straight-line distances or to infer the straight-line distances. Several spatial abilities were also assessed: perceptual discrimination, mental rotation, and visuo-spatial working memory span. The results showed that males outperformed females in spatial inference and mental rotation. Experiment 2 extended the study to old people. The results replicated and clarified those obtained in Experiment 1. Spatial inference and mental rotation showed age-related and gender-related differences; in addition, age reduced the visuo-spatial memory span. Overall, the findings suggest that gender differences favouring males are maximised with tasks requiring active processing and strategic control of metric information.