Given the importance of public information environment in cancer control, it is theoretically and practically important to explore how people's media use to acquire health information influences their beliefs about cancer prevention. In the current research, we focus on the role of the Internet in shaping fatalistic beliefs about cancer prevention (cancer fatalism). To be more specific, we examine the effect of Internet use for health information on changes in cancer fatalism using a 2-wave nationally representative survey. We then investigate whether the effect of Internet use on cancer fatalism is moderated by education and health knowledge. Health-related Internet use reduced cancer fatalism only among those with average and lower than the average levels of education and health knowledge.