Background: Temporary Cardiac Pacing is the temporary delivery of electrical impulses, delivered by electrodes contacting the heart muscles, to regulate and automate the beating of the heart. Aim of the study: (1) Assess nurse's level of knowledge regarding management of temporary pacemaker in critically ill patient, (2) Assess nurse's level of practice regarding care of temporary pacemaker in critically ill patient. Research design: A descriptive exploratory research design was utilized to carry out this study. Setting: This study was conducted in three different cardiac care units at Ain shams university hospital affiliated to Ain Shams University. Tools of data collection: (1) Nurses' knowledge regarding care of temporary pacemaker assessment tool, (2) Nurses' observational checklist. Results: It was revealed that (56%) of nurses had an unsatisfactory level of knowledge regarding care of patient with temporary pacemaker, (56%) of nurses had a satisfactory level of practice pre pacemaker insertion procedure, while (56%) of nurses had unsatisfactory level of practice during the temporary pacemaker insertion procedure, and (56%) of nurses had unsatisfactory level of practice post temporary pacemaker insertion procedure. Conclusion: it can be concluded that more than half of nurses had an unsatisfactory level of knowledge regarding care of patient with temporary pacemaker. More than half of nurses had a satisfactory level of practice pre pacemaker insertion procedure. While more than half of nurses had unsatisfactory level of practice during the temporary pacemaker insertion procedure, and more than half of nurses had unsatisfactory level of practice post temporary pacemaker insertion procedure. Recommendation: future studies are recommended for training programs for nurses to improve their knowledge and practice regarding care of patients with temporary pacemaker.