Abstract Context.—There is increasing interest in ensuring that physicians demonstrate the full range of Accreditation Council for Graduate Medical Education competencies. Objective.—To determine whether it is possible to develop a feasible and reliable multisource feedback instrument for pathologists and laboratory medicine physicians. Design.—Surveys with 39, 30, and 22 items were developed to assess individual physicians by 8 peers, 8 referring physicians, and 8 coworkers (eg, technologists, secretaries), respectively, using 5-point scales and an unable-to-assess category. Physicians completed a self-assessment survey. Items addressed key competencies related to clinical competence, collaboration, professionalism, and communication. Results.—Data from 101 pathologists and laboratory medicine physicians were analyzed. The mean number of respondents per physician was 7.6, 7.4, and 7.6 for peers, referring physicians, and coworkers, respectively. The reliability of the internal consistency, measured by Cr...