Triage is a key principle in the effective management of major incidents and is the process by which patients are prioritized on the basis of their clinical acuity. Therefore, nurses need to educate about triage to improve practice and attitude has a significant impact on patients’ outcomes. This study aims to assessing the effect of educational program regarding patients triage on nurses' practice and attitude. Design: A quasi-experimental study design was used. Setting: The study was conducted at emergency Hospital at Ain shams University Hospitals. The sample included 56 nurses who worked in emergency departments. Tools for data collection: 2 tools are used to collect data mainly: Triage observational checklist and Attitude questionnaire, Results: more than two third (66.1%) of studied nurses were in the age group <30 years with mean age was 29.46±8.54 years. slightly more than half (51.8%) of studied nurses were male and more than one third (42.9%) had diploma. Additionally, slightly more than three quarter (76.8%) were years of experience 1-<10 years., there were improvement of practice regarding triage about nurses in post and follow up program than preprogram. The highest mean score in post program (93.48±10.69) followed by follow up (91.23±10.22) compared to preprogram (75.13±4.66). There were highly statistically significant differences (p<0.001) throughout program phases. Total nurses’ attitude regarding triage through the three phases of the program., more than one third (35.7%) of nurses’ positive attitude in preprogram. It marked improvement of nurse positive attitude of triage (85.7%) in post program phase and the (85.7%) in follow up phase of program. There were highly statistically significant differences throughout program phases, with p-value (p<0.001). Conclusion: According to the current study results, there were improvement of practice regarding triage about nurses in post and follow up program than preprogram, and it marked improvement of nurse positive attitude of triage in post program phase. There was statistically significant improvement. Recommendations: Conduct training program and workshops periodically for nurses about patient's triage in all critical care units to improve practice and attitude of nurses and designing a guideline about roles and responsibilities of triage nurse in emergency departments.