PURPOSE: The purpose of this study was to investigate predictors of nurses' patient safety behavior during inter-hospital transfer. The study was based on the Theory of Planned Behavior (TPB). METHODS: A descriptive survey design was used. Data were collected with a self-administrated 39-item questionnaire completed by 111 nurses from a university hospital in Seoul, South Korea. The questionnaire was developed based on the Theory of Planned Behavior (TPB) guideline and included measure of self- reported past patient safety behaviors, intentions, attitudes, subjective norms and perceived behavioral controls. Ethical approval was granted by the hospital review board. Hierarchical regression analyses were carried out. RESULTS: The average score of patient safety behavior was 4.21±0.63 (5 point scale). The TPB variables explained 49.9%of the variance in patient safety behavior. Intention and subjective norm were the most significant predictors of nurses' patient safety behavior. Attitude was related to nurses'patient safety behavior. CONCLUSION: TPB variables predicted the nurses'patient safety behavior during inter-hospital transfer of patients except for perceived behavioral controls. The results of this study suggest that better strategies for subjective norms and intentions related to patient safety behavior will be helpful in safety culture reform.