Constructivist Internet-based learning environments are advocated by contemporary educators, but few studies investigated students' preferences toward the environments for learning a specific school subject such as science. Therefore, the purpose of this study was to develop a questionnaire to explore students' preferences toward constructivist Internet-based science learning environments. The questionnaire included eight scales: ease of use, relevance, multiple sources, student negotiation, cognitive apprenticeship, reflective thinking, critical judgment and epistemological awareness. The questionnaire responses were gathered from 853 Taiwan high school students. Through factor analysis, these scales revealed highly satisfactory validity and reliability in assessing students' perceptions for Internet-based science learning environments. The students' responses also showed that they strongly preferred the Internet-based learning environments that could connect scientific knowledge with real life situations. Moreover, female students tended to place more emphasis on the instructional guidance offered by the Internet-based environments for science learning, as well as the presentation of scientific knowledge in authentic contexts than did male students. Future research and the implications for Internet-based instruction derived from this study were also discussed. (Contains 3 tables.)