Purpose: This study was done to compare the comprehension and knowledge about delirium in nurses working at long-term care hospitals (NLH) with nurses working at a general hospital (NGH). Method: The participants were 191 nurses from a general hospital and 7 long-term care hospitals in Chungnam. The tool for comprehension consisted of the needs and importance of delirium education and the confidence of management for early detection, caring and prevention of delirium. The tool for knowledge of delirium developed by the author consisted of causing factors, symptoms, caring and prevention of delirium. Result: The comprehension of need and importance of delirium education was higher than the confidence for delirium management in participants. NLH nurses had a higher level in comprehension of the need and importance of delirium education and a lower level in confidence of delirium management than NGH nurses. The mean for delirium knowledge was 75.32% for all participants. The knowledge of NLH nurses was significantly lower than those of NGH nurses. All nurses showed low scores in confidence and knowledge of delirium prevention. Conclusion: A systematic educational program for nurses to enhance the ability for assessment, early detection and prevention of delirium for institutionalized elderly patients needs to be developed.