As web-based learning is becoming more and more popular, the effect of the hypertext navigational structure on knowledge acquisition is gaining interest with both researchers and practitioners. We still, however, lack clear guidelines on how to design such a structure. In this research, we investigate the potential of concept mapping techniques in designing the hypertext navigational structure of web-based learning systems. We also empirically test through a field study the effects of such design methods on the knowledge acquired by the users.