Background: Nurses have a variety of roles and functions associated with the patients' care undergoing cardiac catheterization. Nurses provide care of a patient before, during, and after cardiac catheterization procedure. Aim: This study aimed to assess nurses' performance regarding care of patients undergoing cardiac catheterization. Subjects and Method: Adescriptive research designwas conducted. Setting: At cardiac catheterization unit at Port Said general hospital in Port-Said City and Al-Azhar university hospital in new Damietta city. Sample: A convenient sample of all available nurses (50) worked at previous mentioned settings. Tools: Three tools were used. Tool (I) Nurses' Knowledge Questionnaire. Tool (II) Observational Checklist. Tool (III)Nurses' Attitude Scale. Results: The result of present study indicated  that more than half  of studied nurses had satisfactory level of  knowledgeand practice respectively (52%, 62%) while, most of them (68%) had positive levelof attitude regarding care of patients undergoing cardiac catheterization. Conclusion: More than half of studied nurses had satisfactory knowledge and practice while most of them had positive attitude regarding care of patients undergoing cardiac catheterization. In addition, there were no statistically significant correlation between total nurses' knowledge, practice and attitude scores. Recommendations: There are obvious needs for conducted an educational and training programs to improve nurses knowledge, practice and attitude regarding care of patients undergoing cardiac catheterization.