Stereochemistry is an important topic in organic chemistry. It is also a difficult topic for students to learn. This study investigated the relative effectiveness on students' understanding of three kinds of molecular representations of stereochemistry concepts. Instructional activities compared the use of either: (i) computer-based molecular visualization software; (ii) handheld ball and stick models; or (iii) two-dimensional perspective drawings to represent stereochemical structures. Results showed that computer visualization software could be an effective tool for teaching stereochemistry. (Contains 2 notes and 4 figures.)