Triage is one of the most important managerial and decision making concepts in emergency, it brings the most benefit to the greatest number of patients. Triage is important for redistributing and reducing waiting times and enhancing patient and family satisfaction and improving the quality of health care. Therefore, the aim of this study to determine the effect of implementing triage training competencies on newly graduated nurses (NGNs') working in emergency department (ED) at emergency hospital. Patients and Methods: A quasi experimental research design was utilized during the current study and it was conducted on 50 NGNs' who have a bachelor degree of nursing and are involved in providing direct care for emergency patients in the Emergency Hospital at Mansoura University and who are willing to participate in the study was constitute the study sample (study group). While control group of (25 nurses) who have a bachelor degree of nursing and are involved in providing direct care for emergency patients in Talkha Hospital. Results: The mean triage knowledge score increased immediately and post program implementation for the study group from (32.9±1.73 to 32.6±1.78 out of a total score of 35) compared with (13.44±1.78) to (13.52±2.04) for the control group. Also, triage performance increased immediately and post program implementation for the study group from (135.5±4.26 to 134.42±2.41 out of a total score of 140) compared with (56.44±8.21) to (56.76±7.79) for the control group. Moreover, there was a highly statistical significance difference between the study group and control group in relation to NGNs' knowledge and practice in post and two month post program implementation *p = 0.001. While there was no statistical significant difference between study group and control group in pre program implementation. Conclusion: The findings of this study indicated that there are deficits in triage knowledge and skills of NGNs' working in the ED of the emergency hospital. With these findings it is therefore imperative to establish proper triage training program that will help to establish and improve NGNs' knowledge and skills on triaging in emergency hospital.