One of the more important aptitudes for students studying engineering courses is spatial ability. Spatial ability can be defined as the performance on tasks that require the mental rotation of objects, the skill to understand how objects appear from different perspectives, and the skill to conceptualize how objects relate to each other in space. This aptitude requires visual and perceptual abilities to interpret what is seen, and spatial understanding to mentally manipulate visual representations. Engineering students require these abilities to be effective designers but our understanding of spatial ability and its elements are not well understood. In many respects, spatial ability is not given the attention it deserves. Reported in this paper is research conducted as part of an Australian Learning and Teaching Council funded initiative and the findings of a comprehensive study of the spatial ability of engineering students. Central to the study was a 3D ability test consisting of twelve subtests representing various elements of spatial ability. The test was used to evaluate the performance of engineering students across a range of disciplines and institutions.