Background: Cardiothoracic surgery (CTs) is a cornerstone for treating a variety of cardiovascular and respiratory disorders, and despite its potential to save lives, usually incorporates fatal complications. Postoperative therapeutic exercises are a key intervention for the avoidance or thorough management of these complications. The quality of preoperative health education given to patients can impact their outcomes. Thus, patients' educational programs lay the groundwork for better outcomes and fewer postoperative problems. Study aim:  Evaluate effect of preoperative therapeutic exercises education program on clinical outcomes of patients undergoing CTs. Design: a quasi-experimental design. Setting: Cardiothoracic surgery departments of Cardio-Thoracic Hospital at Zagazig University Hospitals, Alsharqia governorate, Egypt. Subject: A purposive sample of 60 patients who are undergoing CTs. Tools: Patients' assessment interview questionnaire, therapeutic exercises observational checklist, and clinical outcomes assessment system. Results: There was a highly statistically significant improvement and difference between the study and control group patients in terms of knowledge, practice, and clinical outcomes. The study group patients had higher levels of overall knowledge and practice regarding CTs postoperative therapeutic exercises (80.0% and 86.7%, respectively) than the control group (46.7% and 43.3%); in addition to having normal or better clinical outcomes of circulatory, respiratory, wound status, and pain level compared to the control group. Conclusions: The preoperative therapeutic exercises education program is considered an effective nursing strategy for enhancing the clinical outcomes of patients undergoing CTs as it significantly improved the patients' knowledge and practice of cardiothoracic postoperative exercises that in turn improved their clinical outcomes, which reflects its positive effect on patients' outcomes. Recommendations: There should be widespread implementation of the preoperative therapeutic exercises education program in study settings and all comparable ones, including all government hospitals.