Objective: Pediatric endocrinologists (PEs) have historically read their own bone age (BA) X-rays based on the belief that radiologists do not accurately interpret these tests. Whether there are significant differences in BA interpretations between these two groups has not been systematically explored. The objectives of the study were to compare BA readings performed by PEs and radiologists and determine whether clinical variables were associated with discrepancies in readings. Methods: A retrospective chart review of children presenting for initial evaluation of short stature (SS) or precocious puberty (PP) who had a BA X-ray completed was performed. Clinical variables analyzed included age, gender, ethnicity, Tanner stage, body mass index, reason for referral, radiologist location (Children's vs. outside hospital), and PE and radiologist BA readings using the Greulich and Pyle method. Results: Of 103 patients aged 9 ± 3.66 years, there was a discrepancy between the PE and radiologist readings on 70 images (68%). Discrepancy ranged from -1.5 to 3.5 years, with a mean of 4 ± 12 months. Patients referred for PP were more likely to have discrepant interpretations than those referred for SS (8.4 months vs. 0.8 months; P = .007). No differences were seen in interpretations between in-house radiologists and those at outside hospitals. Conclusion: Radiologists interpreted BAs differently than PEs in the majority of images. In patients referred for PP, BAs were interpreted as being older by radiologists than by PEs, perhaps due to bias from the reason for referral. Our results provide support for continued independent BA interpretations by PEs. Abbreviations: BA = bone age; GP = Greulich and Pyle; PE = pediatric endocrinologist; PP = precocious puberty; SS = short stature.