This study investigated university instructors' teaching profiles (rank order of teaching behaviors) as they emerge from student ratings. The data consisted of student ratings of all faculty members in the physics and chemistry departments at Tel Aviv University, with no exception, who taught the same undergraduate course over two consecutive years. The ratings of these instructors were taken twice a semester (at mid- and end of semester), during the two academic years of the study, using a short rating instrument. A (4 × 5) × 2 ANOVA was conducted, with time of measurement and item serving as repeated measures, and department as a grouping factor. The same procedure was used for identifying differences between pairs of measurements for each item. These pairs compared the corresponding measures of the first year versus the second year, and separately those of mid-semester versus the end of semester. Findings indicate a very high degree of stability of instructors' profiles across time of measurement and activities to improve instructor performance on weak points; no clear-cut improvement from mid-to end-of-semester ratings except for teachers who undertake special improvement activities; and differences in teaching profiles for the two academic departments.