BACKGROUND : The ABR Core Examination tests the comprehensive radiology curriculum. On first attempt, 10% of radiology residents fail. This study investigates factors that predict success or failure on the examination. METHODS : An anonymous questionnaire was distributed to all accredited residency programs in diagnostic radiology. Residents who had recently taken the examination answered questions regarding demographics, program, preparation, learning methods, and examination results. Bivariate and multivariate analyses were performed. RESULTS : The study survey was completed by 273 residents. One-tenth of respondents failed or conditionally passed the examination. Residents were more likely to pass the examination if they had trained at an academic program, scored higher on the US Medical Licensing Examination Step 1 and Step 2, achieved higher in-training examination percentile score, completed more practice questions, practiced with both oral and multiple-choice practice questions, and slept longer per night (P < .05 for all). Success was not associated with utilization of specific study resources or protected study time. Lower total number of months spent studying and lower total number of call-containing weeks before the examination were protective factors on multivariate analysis. CONCLUSIONS : Prior performance on standardized examinations predicts success. Training at an academic institution confers an advantage in performance. The ACR In-Training Examination is an appropriate readiness preparation tool. No specific preparation material or resource can guarantee success. Short-duration, high-quality studying is the most effective method of preparation.