Purpose: The purpose of this study was to identify the correlation between level of professional autonomy and clinical decision making abilities in clinical nurses, and to provide basic information for promoting competency nurses in making independent decisions. Method: Data were collected from July 1 to July 18, 2008, and participants were 202 clinical nurses in general hospitals. Collected data were analyzed using descriptive statistics: frequency and percentage and Pearson correlation coefficients with the SPSS WIN 14.0 program. Results: The professional autonomy index for the nurses was 159.63 points. The clinical decision making ability index was 119.79 points. The most highly ranked factor in clinical decision making was search for information and unbiased assimilation of new information. There was a statistically significant difference in professional autonomy according to age, clinical experience, and type of duty. Relation between level of professional autonomy and clinical decision making showed a positive correlation. Conclusion: As a results show a significant correlation between professional autonomy and clinical decision making in clinical nurses, improvement in professional autonomy of clinical nurses, would be promoted through continuous support and training.