Helping students develop criteria for judgment and apply examination skills is essential for promoting scientific literacy. With the increasing availability of the Internet, it is even more essential that students learn how to evaluate the science they gather from online resources. This is particularly true because publishing information on the web is not restricted to experts, and content quality can vary greatly across websites. The responsibility of evaluating websites falls upon the user. Little research has examined undergraduates' evaluation of web sites in science classes. The purpose of this study was to investigate on which websites college students selected and how they evaluated the websites used when developing individual positions about stem-cell research. We used a qualitative approach in search of patterns in undergraduates' website selection and evaluation criteria. We found that students used a variety of web resources from eleven types of websites to complete their independent research report. Students also used eleven evaluation criteria to evaluate these sources, some useful (e.g., credibility) and some not useful (e.g., readability). We found that university students struggled with critically evaluating online resources. Undergraduates need prompts to learn how to critically evaluate the science content provided within websites. This type of scaffold can facilitate useful evaluation and promote critical thinking required for becoming scientifically literate. (Contains 3 tables.)