PURPOSE: The purpose of this study was to describe the essence of the experiences of patients in an ICU, and to understand them from the patients' point of view. METHODS: Participants in this study were six patients in P hospital. Data collection consisted of in-depth interviews and an observation method done from January to April in 2005. The method was analysis using the phenomenological method proposed by Colaizzi(1978). RESULTS: The themes were classified into eight theme clusters. The eight theme clusters were finally grouped into four categories, 'shock', 'pain', 'gratefulness' and 'pleasure of revival'. CONCLUSION: The ICU patients had negative experiences in physical.mental critical situations, but also positive experiences in consolation and nurses and families' encouragement. Therefore, ICU nurses must support patients and their families to minimize the negative experiences and maximize the positive experiences.