Background: Triage is one of the basic components in the emergency department and its correct application improves health care outcomes. Nurses are commonly responsible for the first triage at emergency department. Therefore, their knowledge and practice of triage would greatly affect healthcare prioritizing process. Aim of the study: The study aimed to assess the triage knowledge and practice among nurses in the emergency department. Research design: Descriptive research design was utilized. Setting: The study was conducted in the emergency department, Benha University Hospital. Subject: Purposive sample of 50 nurses of both sex who providing care in the emergency department. Tools: Two tools were used, I: Self-Administered Questionnaire to assess nurses' knowledge regarding triage, and II: Observational checklists to assess nurses' practice regarding triage. Results: 84% of studied nurses had poor level of total knowledge regarding triage and 100% of studied nurses had low level of total practice regarding triage in the emergency department. Conclusion: The nurses' knowledge was poor and their practice was low regarding triage. There was a negative correlation between total knowledge and total practice as evidenced by r(p)= -0.178(0.215). Recommendations: Future study should be conducted to evaluate effect of an educational program regarding triage on nurses' knowledge and practice.