Background: Medication errors are one of the top ten preventable causes of harm in health care settings.They pose a serious threat to patient safety and have the potential to cause serious injury or even death. Despite the fact that early medication errors detection and proper reporting are the first steps in preventing similar ones in the future, the vast majority of errors are not reported. Aim: To investigate barriers to reporting medication administration errors as perceived by nurses working at mansoura university hospital. Research design: A cross-sectional descriptive research design was utilized. Setting: The study was carried out at the inpatient departments affiliated to Mansoura University Hospital in Egypt. Study subjects: A convenience sample of 134 nurses were selected to achieve the aim of the present study. Tools: The data relevant to the study were collected using two tools: nurses'socio-demographic characteristics, and work-related data, and medication administration errors reporting questionnaire. Results: The estimated medication administration error reporting rate was found to be 20%. The most common causes of medication administration errors were nurse staffing (3.5±1.4) and physician communication (3.4 ±1.4). Moreover, the most important barriers to reporting the errors were administrative responses (3.9 ± 1.5) and fear of reporting errors (3.7± 1.6). Conclusion: The current study concluded that 80% of medication administration errors were not reported. Moreover, the common causes of MAE were factors related to nurse staffing and physician communication. Furthermore, the two significant barriers preventing nurses from reporting medication-related errors were administrative response and fear. Recommendation: Healthcare institutions should create a system that incorporates incident reports and a safe work environment free from punishment and blaming to raise the rate of medication error reporting.