Background: The main purpose of nursing is medical care and improving human health. However, nurses medical errors has negative impacts on their function and result of medical care for its recipients. During the delivery of health care, Incidence of medical errors can have grave consequences for patients. The solution to identify and manage clinical errors, are reporting and registration by nurses. The aim of this study was to identify barriers to self- reported error by nurses in the Police hospitals. Materials and Methods: This cross-sectional study was conducted in Police hospitals. Samples selected by quota method and randomly. 273 samples recruited for the study and the instrument was a questionnaire that was made by researcher consists of three parts. Firstly, included demographic information, the second part consists of 4 areas: managerial factors, fear of the reporting consequences, reporting processes, ethical components) and finally it was involved closed questions. Obtained information were analyzed by using descriptive and inferential statistical methods , the correlation coefficient ,and chi- 2 with SPSS 21. Results: According to the results, barriers to self- reporting errors by nurses are respectively related to fear of the reporting consequences (51.12±11.97), managerial factors (33.5±7.23), reporting processes (23.15±5.07) and ethical factors (21.89±4.92). Also there was no significant relation between clinical errors with gender, occupational category, type of employment and education(P>0.05). Conclusion: Since then, fear of the consequences of reporting is the important barrier of self- reported error by nurses, managers should provide the career support , educate scientifically and continuously to the nurses, and reduce their concerns in this case.