PURPOSE: The study was conducted to survey intensive care unit nurse's knowledge, nursing performance, and stress involving delirium. METHODS: The subjects of this study were 278 nurses from three hospitals in Seoul, who had worked at the intensive care unit more than six months. Data were collected using questionnaire from December, 2005 to January, 2006. RESULTS: The mean score of knowledge about delirium was 31.60 out of 50 and it was significantly lower among those with clinical experience of 12-35 months and 60-119 months and those who didn't experience conflicts with patients' families. The mean score of nursing performance for delirium was 16.10 out of 23, and it was significantly higher among those who took care of 2 patients. The mean score of stress related to delirium was 63.92 out of 100, and it was significantly higher among those aged over 40, nurses who were university graduates, nurses who experienced conflicts with patients' families, and nurses who took care of 5 patients. CONCLUSION: We need to develop systematic education programs in charge of patients with delirium.