Purpose: The purpose of this study was to develop a scale to assess the transition shock experienced by newly graduated nurses, and test thevalidity and reliability of the scale. Methods: The initial items were identified through a review of literature and in-depth interviews with ninenewly graduated nurses. Content validation of the items was evaluated by five nurse professors and three nurses. Participants were 269 newlygraduated nurses who worked at six acute care hospitals in Busan, Ulsan, and Yangsan, South Korea. Data were analyzed using item analysis,exploratory and confirmatory factor analysis, criterion related validity, and internal consistency. Results: The final scale consisted of 18 items andsix factors (conflict between theory and practice, overwhelming workload, loss of social support, shrinking relationship with co-workers, confusionin professional nursing values, and incongruity in work and personal life), which explained 71.3% of the total variance. The six subscalemodel was validated by confirmatory factor analysis. Cronbach’s alpha for the total items was. 89. Convergent validity was evaluated by analyzingtotal correlation with burnout (r=.71, pqqqlt;.001) and turnover intention (t=5.84, pqqqlt;.001). Conclusion: This scale can be used in the developmentof nursing interventions to reduce the transition shock experienced by newly graduated nurses.