Background: Interventions to improve pediatric trainee education in palliative care have been limited by a lack of reliable and valid tools for measuring effectiveness. Objective: We developed a questionnaire to measure pediatric fellows' self-efficacy (comfort), knowledge, and perceived adequacy of prior medical education. We measured the questionnaire's reliability and validity. Methods: The questionnaire contains questions regarding self-efficacy (23), knowledge (10), fellow's perceived adequacy of prior medical education (6), and demographics. The survey was developed with palliative care experts, and sent to fellows in U.S. pediatric cardiology, critical care, hematology/ oncology, and neonatalperinatal medicine programs. Measures of reliability, internal consistency, and validity were calculated. Results: One hundred forty-seven fellows completed the survey at test and retest. The self-efficacy and medical education questionnaires showed high internal consistency of 0.95 and 0.84. The test-retest reliability for the Self-Efficacy Summary Score, measured by intraclass correlation coefficient (ICC) and weighted kappa, was 0.78 (item range 0.44-0.81) and 0.61 (item range 0.36-0.70), respectively. For the Adequacy of Medical Education Summary Score, ICC was 0.85 (item range 0.6-0.78) and weighted kappa was 0.63 (item range 0.47-0.62). Validity coefficients for these two questionnaires were 0.88 and 0.92. Fellows answered a mean of 8.8/10 knowledge questions correctly; percentage agreement ranged from 65% to 99%. Conclusions: This questionnaire is capable of assessing self-efficacy and fellow-perceived adequacy of their prior palliative care training. We recommend use of this tool for fellowship programs seeking to evaluate fellow education in palliative care, or for research studies assessing the effectiveness of a palliative care educational intervention.