A composite theory of college science student note-taking strategies was derived from a periodic series of five interviews with 23 students and with other variables, including original and final versions of notes analyzed during a semester-long genetics course. This evolving composite theory was later compared with Van Meter, Yokoi, and Pressley's (Journal of Educational Psychology, 86, 323–338, 1994) corresponding composite “college students' theory of note-taking.” Students' notes in this long-term study were also compared with a standard of “adequate” note-taking established by experts. Analyses detected many similarities between the two composite theories. Analyses also provided evidence of inadequate note-taking strategies, inconsistencies between what students claimed and evidently did with their notes, and weak self-regulating learning strategies. Recommendations included prompting students during class on how to take notes. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 786–818, 2006