The World Wide Web is increasingly becoming an important source of information for healthcare professionals. However, finding reliable information from unauthoritative Web sites to inform healthcare can pose a challenge to nurses. A study, using grounded theory, was undertaken in two phases to understand how qualified nurses judge the quality of Web nursing information. Data were collected using semistructured interviews and focus groups. An explanatory framework that emerged from the data showed that the judgment process involved the application of forms of knowing and modes of cognition to a range of evaluative tasks and depended on the nurses' critical skills, the time available, and the level of Web information cues. This article mainly focuses on the six evaluative tasks relating to assessing user-friendliness, outlook and authority of Web pages, and relationship to nursing practice; appraising the nature of evidence; and applying cross-checking strategies. The implications of these findings to nurse practitioners and publishers of nursing information are significant.