This paper describes the development and implementation of a new evaluation format for assessing professional attitudes in medical laboratory technology students--the performance appraisal. This tool measures attitudes considered desirable in the ¿ideal technologist¿, and links the presence or absence of these attitudes to behaviors which can be observed in the student. The performance appraisal functions not only as an evaluation instrument for instructors, but as a learning tool for students, who can identify behavioral objectives, assess their own progress, and set goals and strategies for development of professional attitudes. Details regarding the administration of the evaluation instrument, such as rating scales, remedial planning, and responsibilities of faculty, clinical coordinators, and students are presented. In addition, controversies regarding the evaluation of professional attitudes are discussed, including: optimizing instructor objectivity; timing and grading of evaluations; forwarding of evaluations from one instructor to another; identification of mandatory and desirable attitudes; and criterion referencing of objectives. Plans for future development of the system are included.