Background: Functional health status assessment among patients with a coronary artery bypass graft (CABG) over time is very crucial.Aim: to determine the functional health status of patients undergoing coronary artery bypass graft. Research design: A descriptive exploratory research design. Setting: The study was conducted in cardiothoracic surgery department at Assiut University Heart Hospital. Sample: A purposive sample of 100 adult male and female patients. Tools: Tool (I) Patient assessment sheet and Tool (II) Biopsychosocial functional health status. Results: The majority of the studied patients had a partially dependent physical function in the pre (68%) and post-operative phase (66.0%) while follow-up was independent (36.4%). Moderate psychological distress was reported in three phases (preoperative (51.0%), postoperative (81.0%), and follow-up phase (93.0%). Also, moderate social dysfunction in the preoperative period was experienced by patients (57.0%) while they had mild social dysfunction in the post-operative (31.0%) and follow-up phases (2.0%). Conclusion: Functional health status was improved after (CABG) surgery in the follow-up phase, particularly in physical function. Recommendations: Establishing a simplified and illustrated educational booklet regarding therapeutic compliance to improve functional health status for patients undergoing coronary artery bypass graft.