Objectives: This study aims to show whether correlation exists between pediatric residency applicants’ quantitative scores on the United States Medical Licensing Exam Step 2 Clinical Knowledge examination and their subsequent performance in residency training based on the Accreditation Council for Graduate Medical Education Milestones, which are competency-based assessments that aim to determine residents’ ability to work unsupervised after postgraduate training. No previous literature has correlated Step 2 Clinical Knowledge scores with pediatric residency performance assessed by Milestones. Methods: In this retrospective cohort study, the United States Medical Licensing Exam Step 2 Clinical Knowledge Scores and Milestones data were collected from all 188 residents enrolled in a single categorical pediatric residency program from 2012 - 2017. Pearson correlation coefficients were calculated amongst available test and milestone data points to determine correlation between test scores and clinical performance. Results: Using Pearson correlation coefficients, no significant correlation was found between quantitative scores on the Step 2 Clinical Knowledge exam and average Milestones ratings (r = -0.1 for post-graduate year 1 residents and r = 0.25 for post-graduate year 3 residents). Conclusions: These results demonstrate that Step 2 scores have no correlation to success in residency training as measured by progression along competency-based Milestones. This information should limit the importance residency programs place on quantitative Step 2 scores in their ranking of residency applicants. Future studies should include multiple residency programs across multiple specialties to help make these findings more generalizable.