Introduction: Hypoxemia is a common finding among critically ill patients irrespective of their underlying diagnosis. this study Aimed to evaluate the Effect of implementing teaching program on nurses' performance regarding hypoxia for critically ill patients. Design: Quasi experimental design was used in the current study. A convenience sampling of 30 nurses participated in this study. Two tools ;I were utilized knowledge assessment' questionnaire and observational checklist. Method; The teaching program was conducted over 10 repeated lectures during different working morning shifts in an average of 6 sessions per week for one month; each lecture was taking about 1.5 hours. The instructional program included presentation and watching some educational videos for the practical skills related to care of hypoxia. Results: the results revealed that nurses had lack of knowledge and practices regarding hypoxia in the critical care department, however, the hypoxia teaching program showed a positive impact in improving nurses’ knowledge and practice regarding hypoxia. Conclusion: The designed instructional program was having an effective, sustainable impact on improving nurses’ knowledge and practice regarding hypoxia in the critical care department. Recommendations: Implementation of continuous education programs regarding hypoxia can play a part in supporting clinical practice. Keywords: Critically Ill, hypoxia, Nurses' performance & Teaching Program