Purpose: Class climate is defined as the general attitude of instructors and students in class. Analysing the instructor s behavior helps build a desirable class climate and improves academic achievement and class instruction. Methods: The checklist using a five-point scale and consisting of 28 pairs of contrary adjectives was divided into four categories of creativeness, activeness, precision, and mildness. Two different classes taught by one instructor were studied. There were five supervisors for this study and a simple statistical analysis was done. Results: For the undergraduate class, the observers assessments showed the lowest overall point in activeness and the highest in mildness. In general, points given by the instructor were higher than the supervisor s and the student s. Conclusion: The instructor s perception of the class was more positive than the observers and the students . This means that all tested categories need to be improved. One way of dealing with this problem for the instructor is to set up a meeting with the supervisor and design a class climate improvement plan.