The purposes of this study were to determine the factors that influence job satisfaction for ICU nurses and to analyze group differences in job satisfaction based on the nurses' preference and perception of the work environment with an enhanced professional role. A total of 231 nurses who had been working in Intensive Care Units at least for 6 months at selected university hospitals participated in the study while head nurses or those with administrative positions were excluded. The study participants had an average of 33 months of clinical experience with an age range of 23 to 40 years. The data were analyzed by utilizing SPSSWIN and the results are as follows. 1) Hierarchical multiple regression analysis showed that work characteristics defined by Job characteristics theory and nurses' preference/ perception of ideal work environment together explained 33% of variance in job satisfaction. Skill variety, task identity and autonomy as well as individual perception of work environment were significant variables for explaining job satisfaction. Job satisfaction was not significantly related to age, marital status, education, and clinical experience. 2) The groups classified by nurses' preference and perception of work environment were significantly different in their job satisfaction. Nurses with high preference and high perception showed significantly higher general and specific job satisfaction than other nurses. The nurses who showed high preference but perceived their work environment as not reflecting ideal job characteristics reported the lowest job satisfaction among the groups. In conclusion, the role of individual preference and perception of the work environment in explaining the relationship between the redesign of work environment and job satisfaction was supported by the study. The preferences of nurses to the innovative work characteristics should be considered in the process of enhancing job characteristics to lead job satisfaction and low turn over and ultimately to improve quality of care.