Interpersonal communication skills and professionalism competencies are difficult to assess among nephrology trainees. We developed a formative "Breaking Bad News" simulation and implemented a study in which nephrology fellows were assessed with regard to their skills in providing counseling to simulated patients confronting the need for kidney replacement therapy (KRT) or kidney biopsy. Observational study of communication competency in the setting of preparing for KRT for kidney failure, for KRT for acute kidney injury (AKI), or for kidney biopsy. 58 first- and second-year nephrology fellows assessed during 71 clinical evaluation sessions at 8 training programs who participated in an objective structured clinical examination of simulated patients in 2017 and2018. Fellowship training year and clinical scenario. Primary outcome was the composite score for the "overall rating" item on the Essential Elements of Communication-Global Rating Scale 2005 (EEC-GRS), as assessed by simulated patients. Secondary outcomes were the score for EEC-GRS "overall rating" item for each scenario, score< 3 for any EEC-GRS item, Mini-Clinical Examination Exercise (Mini-CEX) score< 3 on at least 1 item (as assessed by faculty), and faculty and fellow satisfaction with simulation exercise (via a survey they completed). Nonparametric tests of hypothesis comparing performance by fellowship year (primary goal) and scenario. Composite scores for EEC-GRS overall rating item were not significantly different between fellowship years (P= 0.2). Only 4 of 71 fellow evaluations had an unsatisfactory score for the EEC-GRS overall rating item on any scenario. On Mini-CEX, 17% scored< 3 on at least 1 item in the kidney failure scenario; 37% and 53% scored< 3 on at least 1 item in the AKI and kidney biopsy scenarios, respectively. In the survey, 96% of fellows and 100% of faculty reported the learning objectives were met and rated the experience good or better in 3 survey rating questions. Relatively brief time for interactions; limited familiarity with and training of simulated patients in use of EEC-GRS. The fellows scored highly on the EEC-GRS regardless of their training year, suggesting interpersonal communication competency is achieved early in training. The fellows did better with the kidney failure scenario than with the AKI and kidney biopsy scenarios. Structured simulated clinical examinations may be useful to inform curricular choices and may be a valuable assessment tool for communication and professionalism.