Purpose:The purpose of this study was to examine the knowledge, attitude and performance of nurses in a tertiary hospital and to identify factors that affected their performance toward older adults. Methods: The data were collected from 109 nurses working in a tertiary hospital located in S-city, South Korea. The questionnaire consisted of questions about knowledge, attitude and performance of the nurses and their general characteristics. The Knowledge about Older Patients Quiz (KOP-Q) was used to measure knowledge of the older adults. The analyses included descriptive statistics, an independent t-test, ANOVA and a multiple regression analysis. Results: Statistically, the nurses' attitudes toward older adults differed significantly according to their marital status and work unit. The nurses' work units (p=.004) and work positions (p<.001) influenced their performance with regard to older adults after controlling their general characteristics. Nurses in medical units performed better than nurses in intensive care units and charge nurses and nurse educators performed better than staff nurses. Conclusion:The results can be used to plan and implement educational programs to improve gerontological nursing practices. In addition, the factors influencing performance of nurses can be used as foundational data for developing ways to improve nursing outcomes for older adults.