In recent years, colleges have been moving from traditional, classroom-based student evaluations of instruction to online evaluations. Because of the importance of these evaluations in decisions regarding retention, promotion and tenure, instructors are justifiably concerned about how this trend might affect their ratings. We recruited faculty members who were teaching two or more sections of the same course in a single semester and assigned at least one section to receive online evaluations and the other section(s) to receive classroom evaluations. We hypothesised that the online evaluations would yield a lower response rate than the classroom administration. We also predicted that there would be no significant differences in the overall ratings, the number of written comments, and the valence (positive/neutral/negative) of students' comments. A total of 32 instructors participated in the study over two semesters, providing evaluation data from 2057 students. As expected, online evaluations had a significantly lower response rate than classroom evaluations. Additionally, there were no differences in the mean ratings, the percentage of students who provided written comments or the proportion of comments in the three valence categories. Thus, even with the lower response rate for online evaluations, the two administration formats seemed to produce comparable data.