Objective: Critical care nurses face some of the most daunting ethical challenges in clinical practice. Nurses who work in intensive care and emergency rooms, and other highly specialized settings must have the ability to recognize the various ethical issues they face in the care of patients daily and to be prepared to address them in collaboration with patients, families, colleagues and administrators. Ethical comportment skills are similar to clinical skills, in which they can be learned and can be improved over time through using of several strategies and appropriate role modeling. The aim of the work was to measure changes in attitude, practice and knowledge of undergraduate nursing students after receiving an educational intervention in ethical comportment in critical care nursing. Methods: The study design was a quasi-experimental research design. Setting: this study was conducted at Alexandria University, Faculty of Nursing, at Critical Care & Emergency Nursing Department. Subjects of this study included 70 nursing students who completed the study. The tool of this study is "ethical comportment in critical care nursing students' assessment tool". It is used to assess students' attitude, knowledge and practice regarding ethical comportment. Results: The levels of students' attitude, knowledge and practice towards items of ethical comportment increased after receiving an educational intervention in ethical comportment and the differences between attitude, knowledge and practice of student nurses towards items of ethical comportment pre and post the educational intervention were statistically significant. Conclusions: From the findings of the current study it can be concluded that performing an educational intervention in ethical comportment can help in developing ethical comportment skills in critical care nursing students. Recommendation: nurses training should begin in the undergraduate level and must focus on the development and promotion of attitudes from which and acts by which care is provided.