Background: There are many factors that affecting nurse's performance regarding
post -operative care of patient with open-heart surgery. This factor should be detected and
solved to improve quality of nursing care to improve outcome of patient. Aim: This study
aims at assessing factor affecting nurses' performance regarding post-operative care of
patient with open-heart surgery through the following: level of knowledge, practice and
attitude in addition to factors affecting nurses' performance regarding post-operative care of
patient with open-heart surgery. Study design: descriptive research design was selected to
fulfill the aim of the study. Setting: This study was conducted in post cardiothoracic ICU at
academic institute for heart surgery at Ain shames university hospital. Subject: A convenient
sample of all available nurses (36 nurses) working in study setting (ICU unit) + (intermediate
unit). Data collection tools: A-Self-administered nurses' questionnaire to assess nurses
demographic data of nurses under study, level of nurses' knowledge, attitude and factors
affecting nurses' performance regarding post- operative care of patient with open-heart
surgery. B- Nurses' observational checklist to assess nurses' level of practice regarding
post- operative care of patient with open-heart surgery. Result: The result of this study
revealed that about tow third of studied nurses' got satisfactory level of knowledge regarding
post -operative care of open- heart surgery patient, about tow third of nurses' under the study
had positive attitude toward post -operative care of open- heart surgery patient and about
more than have of nurses' under the study got total satisfactory level of practice toward post
-operative care of open- heart surgery patient. Recommendation: In service, training
program/courses must be developed based on need assessment for nurses' regarding critical
management of post-operative patient with open-heart surgery