OBJECTIVE: The purpose of this study was to develop and validate a brief, reliable rating scale to measure resident surgical competency. STUDY DESIGN: For 12 months, the gynecology faculty at Johns Hopkins Bayview Medical Center completed a prototype global rating scale after each surgery. Concurrently, each resident completed the same assessment form as a self-evaluation. Factor analysis, Cronbach's alpha, Pearson correlations, and one-way analysis of variance were used to evaluate internal consistency and validity. RESULTS: Using factor analysis, the assessment form was modified to create the Hopkins Assessment of Surgical Competency (HASC). This contained 2 scales, General Surgical Skills and Case Specific Surgical Skills. The Cronbach's alpha ranged from 0.86 to 0.89. The item-scale Pearson correlations ranged from 0.74 to 0.87. Senior residents scored significantly higher than junior residents and last rotation scores were significantly higher than the first. CONCLUSION: The HASC is a concise, valid, and reliable tool for assessing surgical competency in the clinical setting.