Abstract Introduction: The pulvinar, located adjacent to the medial wall of the acetabulum, consists of fat and fibrous tissue and may prevent medialization of the femoral head during a reduction attempt. Patients experiencing hip pain who undergo hip arthroscopy may exhibit varied appearances of pulvinar pathology. The precise significance of these variations remains unknown. The purpose of this study was to evaluate the inter-observer reliabilities of two grading systems for the pulvinar to allow for future study. Methods: 300 intraoperative arthroscopic photographs of the pulvinar were reviewed by 9 hip preservation surgeons. Images were reviewed for quality and assessed into two classification systems, denoted as System A (descriptive) and System B (Likert). System A consisted of six descriptive options: normal, mild synovitis, inflamed/hemorrhage, hyperplasia, fibrotic, and other (namely PVNS, synovial chondromatosis, etc.). Alternatively, System B included four-point Likert scale: normal, mild synovitis, moderate synovitis, and severe synovitis. A power analysis was conducted prior to initiating the study, revealing that a minimum sample size of 251 would result in a 95% confidence interval with a margin of 0.1 when the kappa statistic reached at least 0.60. Statistical examination was performed to provide a Fleiss Kappa score with a 95% confidence interval. Agreement was classified as poor for <0, slight for 0-0.2, fair for 0.21-0.4, moderate for 0.41-0.6, substantial for 0.61-0.8, and almost perfect for >0.8. Results: A total of 300 intraoperative arthroscopic photographs of the pulvinar were reviewed and rated. System A demonstrated an inter-observer reliability of ĸ=0.31 (0.27-0.36). System B demonstrated an inter-observer reliability of ĸ=0.64 (0.62-0.66). Some concern was made by examining surgeons about 46 images possibly being suboptimal. When these were removed, inter-observer reliability of System A improved to ĸ=0.40 (0.36-0.44) whereas System B was unaffected. Conclusion: Interobserver reliability for the pulvinar when viewed arthroscopically was substantial for a Likert based rating system and fair to moderate for a descriptive based classification. Understanding and development of these classification systems may allow further investigation to create treatment algorithms for pulvinar pathology. Keywords: Pulvinar, Hip Pain, Hip Arthroscopy