Numerous studies have shown that sex differences in visuospatial tasks vary in size and direction depending on the nature of the task, with large differences favoring males on tasks that require transformations in visuospatial working memory. The cognitive processes underlying these differences were investigated using laboratory tasks developed by Dror and Kosslyn (1994). Four cognitive components of visuospatial working memory were assessed--image generation, maintenance, scanning, and transformation--in an attempt to identify the components that would show differential effects for females and males. The image generation task required retrieval of shape information from long-term memory, generation of a visual image in working memory, and utilization of the information about the shape in a decision task. The image maintenance task required only the latter two processes. The information processing demands required by scanning and rotation tasks came from the need to transform the visual image so that it could be used in decision making. Males responded more quickly on all four tasks (ds between .63 and .77), with no between-sex differences in accuracy. We concluded that speed of processing is central to understanding sex differences in visuospatial working memory. We discuss implications of these findings for performance on real-world visuospatial tasks.