Background: Cardiac catheterization is an invasive procedure indicated in a wide variety of circumstances. It is used for diagnostic evaluation and therapeutic intervention in the management of patients with cardiac diseases. Aim of the study: this study aimed to assess nurse's knowledge and practice regarding patients undergoing cardiac catheterization. Research design: descriptive research design was utilized in this study.Setting: the study was conducted in cardiac catheterization unit at Assiut University Hospital. Participants: A convenience sample including all nurses working (24) at cardiac catheter unit who are willing to participate in the study.Tools: A) Structured interview questionnaire sheet. b) Observation checklist sheet. Results: the results showed that; the highest percent of nurses (41.7%) their age was more than 30 years and have diploma degree; (62.5%). Their years of experience ranged from5 to 10years (41.7%). The majority of nurses (87.5%) had no in-service training courses related to cardiac catheterization and heart disease. Conclusion: nurses showed inadequacy of their knowledge and practice regarding care of patients undergoing cardiac catheterization. Recommendations: Nurses are need for in-service training programs and refreshing courses to improve their knowledge which will reflect into their knowledge and practice while working with patients.