Background and objectives: Medication errors can cause serious problems to patients and health system. Initial results of medication errors increase duration of hospitalization and costs. The aim of this study was to determine the reasons of medication errors and the barriers of errors reporting from nurses’ viewpoints.

Material and Methods: A cross-sectional descriptive study was conducted in 2013. The study population included all of the nurses working in Tabriz Sina hospital. Study sample was calculated 124 by census method. The data collection tool was questionnaire and data were analyzed using SPSS software version 20 package.

Results: In this study, from the viewpoint of nurses, the most important reasons of medication errors included the wrong infusion speed, illegible medication orders, work-related fatigue, noise of ambient and shortages of staff.  Regarding barriers of error reporting, the most important factors were the emphasis of the directors on the person regardless of other factors involved in medication errors and the lake of a clear definition of medication errors.

Conclusion: Given the importance of ensuring patient safety, the following corrections can lead to improvement of hospital safety: establishing an effective system for reporting and recording errors, minimizing barriers to reporting by establishing a positive relationship between managers and staff and positive reaction towards reporting error. To reduce medication errors, establishing training classes in relation to drugs information for nurses and continuing evaluation of personnel in the field of drug information using the results of pharmaceutical information in the ward are recommended.