Objective: The purpose of the study was to determine the level of autonomy among nurses and to examine the professional and institutional factors that affect autonomy. Material and Methods: We carried out this descriptive, cross-sectional study on 582 nurses working in three hospitals. We used two forms for data collection. The first was the personal information form with 21 questions including factors that affect autonomy in clinical nurses. The second was the 30-item autonomy subscale of the Sociotropy/Autonomy Scale (SAS). Results: Response rate was 79.6% (n = 582). Based on the research findings, the mean General Autonomy (GA) score among nurses was 75.95 +/- 16.22. Although no statistically significant difference was found for GA and Autonomy Subfactors (ASF) score means regarding educational degree, the level of autonomy increased as the educational degree increased. The status of reading scientific publications and the status of participating in continuing education programs increased the GA level of nurses (p < 0.05). We did not find a significant difference for GA levels between institutions (p > 0.05). Conclusion: Considering that the possible range of scores for GA is 0-120, we suggest that the general level of autonomy for nurses is moderate.