An observational rating instrument was developed to measure affective traits of medical technology students. Fourteen categories of behavioral traits evaluated by medical technology programs were identified, based on results of a national survey. These traits were then grouped according to the affective domains established by Krathwohl, Bloom, and Masia (1971). Affective objectives were developed for medical technology students, including the following: being attentive and demonstrating an attitude of appropriate response to instructions and duties, showing a value system consistent with clinical laboratory prefessionalism and the ability to set priorities for tasks, and internalizing the values. In addition, 49 behavioral statements that defined the affective traits were identified and incorporated into a questionnaire, which was administered to medical technology education coordinators and instructors in Pennsylvania. Thirty respondents classified each behavior according to the most appropriate behavior category and rated each behavior according to its importance in the role of the medical technologist. Findings resulted in 31 affective traits that were used in the final instrument, a Likert-type scale for rating students. A literature review, bibliography, questionnaire, list of schools surveyed, and instructions for using the evaluation form are included. (SW)