Quality improvement (QI) initiatives require leaders who can facilitate change through negotiation. Although a few education programs teach these skills, there is no published literature on methods to assess competency in negotiation. This study's purpose was to determine the psychometric properties of an Objective Structured Clinical Examination (OSCE) to assess negotiation skills. The OSCE uses an actor trained to respond to the learner in a standardized fashion. The negotiation station was part of an 8-station QI OSCE piloted in the Mayo Clinic Endocrinology and Preventive Medicine fellowship programs. External experts judged the content validity to be excellent. Interrater reliability was outstanding for the global competency assessment (0.80) and moderate for checklist scores (0.53). All participating faculty strongly agreed (33.3%) or agreed (66.7%) that the OSCE station was an authentic assessment tool. Further research is needed to study the predictive validity of such an OSCE and its application to assessing other quality improvement competencies. (Am J Med Qual 2008;23:350-355)