Purpose: The purpose of this study was to determine undergraduate students` level of knowledge, attitude, and confidence toward patient safety. Methods: A descriptive survey design was used. The subjects consisted of 932 senior nursing students who have had clinical practice in nursing schools in a metropolitan city in Korea. The data were collected from March 4th to 28th in 2011. Knowledge, attitude, and confidence on patient safety were measured using self administered questionnaires. Data were analyzed with SPSS 18.0 using descriptive statistics, t-test, One-Way ANOVA, and Pearson correlation coefficient. Results: Knowledge of patient safety was relatively low and attitude and confidence were at moderate level. There were statistically significant differences in knowledge, attitude, and confidence toward patient safety according to gender, educational system, grades, satisfaction with nursing major or clinical practice, and experience of patient safety education or patient safety campaign. There was a significant positive correlation among knowledge, attitude and confidence on patient safety. Conclusion: The study findings suggests that concept and skills on patient safety need to be educated systematically during undergraduate curriculum linked with clinical practicum.