Research suggests that the World Wide Web (WWW) represents the intersection of at least two domains: content and technology. This investigation was designed to examine the relationship between prior knowledge and WWW browsing outcomes (i.e., navigation behavior and knowledge gain) within the context of a genetics Web site. Students randomly assigned to a treatment group were given a prereading activity designed to increase their prior knowledge within the domain of genetics. This group demonstrated significantly higher learning outcome scores than students in the control group. The treatment group also spent more time browsing, viewed more multimedia resources, and utilized more in-text embedded links. These results and others are interpreted in terms of instructional decisions and recommendations for future research.