Purpose: The purpose of this study was to assess the educational needs of ICU nurses based on an analysis of importance, frequency, and difficulty for ICU nursing practice. Method: A cross-sectional survey was conducted using a questionnaire with 80 questions in 14 ICU nursing categories. Data were collected from August to October 2009. A total of 295 ICU nurses from five hospitals who had minimum of one year clinical experience participated. Data were analyzed with using descriptive statistics. Results: For importance, emergency care had the highest score, followed by physical assessment, communication, cardiovascular care, and ICU basic nursing. Regarding the frequency, physical assessment had the highest score, followed by communication, medication, ICU basic nursing, and respiratory care. Cardiovascular care was the most difficult task, followed by neurological care, emergency care, other ICU related nursing care, diagnostic test, and communication. Conclusion: The findings indicate a high educational need in the areas of communication, medication, physical assessment, diagnostic test, emergency care, and cardiovascular care. Thus the development of educational programs on communication, medication, physical assessment, diagnostic test, emergency care, and cardiovascular care are needed for ICU nurses.