Engineers communicate with one another largely by graphical means. For this reason, it is very important that the spatial visualization abilities of engineering students be well-developed. Unfortunately, there is little guarantee that our students come to the university with well-developed spatial abilities. In this paper we will compare the spatial visualization skill-levels for entering engineering students from our universities by means of several tests (Mental Rotations Test, Mental Cutting Test, and Differential Aptitude Test: Space Relations) and evaluate our experiences in improving the spatial abilities of both male and female engineering students. Through international comparisons of our experiences in teaching introductory courses, we will describe the teaching methods that seem to be especially helpful in the development of spatial visualization skills for engineering students.