Background:  The COVID-19 pandemic has a negative effect on critical care nurses' mental health. Aim: This study aimed to assess the level of post-traumatic stress disorder (PTSD) among the critical care nurses caring for patients with COVID 19 and evaluate the stress factors that affect them. Study design and Methods: A descriptive cross-sectional study was conducted in the intensive care and emergency units at Assiut University Hospital from the period of August 2020 to November 2020; 118 critical care nurses completed the questionnaire via an online survey. Results: Among the participating nurses (47.5%) were reported moderate level of post-traumatic stress disorder symptoms, and (39.0%) were reported severe level of PTSD symptoms. At P=0.05, there was a positive significant correlation between PTSD and workload, COVID 19 patient death, conflict with physician, lack of competency, and fear of infection among participant nurses (r =.370^**, r = .268^**, r = 268^**, r = .265^**, r = r =.272^**, r =.277**) respectively. Conclusion: The rate of post-traumatic stress disorder was higher among critical care nurses caring for patients with COVID-19. Recommendations: We recommended further study to investigate the impact of the COVID-19 on mental health of critical care nurses and educate them about PTSD.