Results of this study identified "evidence markers" that characterize reflection in preservice teacher electronic portfolios. Examples of such markers include openness to self-learning, willingness to self-critique, analytical detail of reflections, and taking responsibility for pupil learning challenges. To identify the markers, school of education faculty members, while reviewing student teachers' electronic portfolios, verbalized judgments that they were making about the portfolio author's reflective ability and cited the portfolio evidence that supported those judgments. Analysis of session transcripts identified some three-dozen evidence markers. Using these markers, a rubric was developed for assessing student teacher reflective ability based on evaluating his or her electronic portfolio. An experimental study using the rubric to rate student teacher portfolios found supporting evidence for reliability and validity of the rubric, and by implication, provided validation for the evidence markers. Being able to explicitly recognize and characterize the evidence that identifies reflection should assist instructors in teaching the skills of reflection and in making better use of electronic portfolios for promoting reflection among preservice teachers. (Contains 3 figures and 4 tables.)