This study aims to investigate the factors affecting shift nurses' retention to solve the nurse shortage problem. The independent variables were general characteristics, stress response, work-life balance, and grit. The subjects for the study were 214 nurses working in three shifts at three general hospitals in Korea. Data were collected from 1 to 31 August 2022. We used structured tools such as the Nurses' Retention Index, Stress Response Inventory, Work-Life Balance Scale, and Clinical Nurse's Grit Scale. Data analysis was conducted using descriptive statistics, independent sample -test, one-way variance analysis, Pearson correlation analysis, and hierarchical multiple regression analysis. Age, job satisfaction, and grit were factors that had a significant impact on retention intention. Grit had the greatest impact on retention intention. Additionally, retention intention increased in those aged from 30 to 40 years as compared with those under the age of 30. It is necessary to develop and implement a program that can improve grit to enhance the retention intention of shift nurses. Additionally, it is necessary to actively seek measures to reduce dissatisfaction with nursing jobs, increase satisfaction, and manage human resources considering the characteristics of age groups.