Abstract Background Cardiac Rehabilitation (CR) is a multidisciplinary approach for secondary prevention of coronary heart diseases as well as its comorbid psychological disorders such as depression. Its importance is not well established like other secondary prevention measures although it is one of the most cost-effective methods. Objectives The aim of this study is to examine the effect of the cardiac rehabilitation on depression symptoms in patients after acute coronary events and potential improvement in patient prognosis and reduction of overall morbidity and mortality. Methods This analysis is a double armed intervention study that was conducted in the period between March 2018 and August 2018 on 60 patients who were referred to the CR clinic after surviving acute coronary events. Patient selection was done so that a study group of 30 patients who completed the CR program and a control group of 30 patients who dropped out early from the CR program were included. It included mainly Egyptian patients who were referred the Ain Shams University Hospital CR clinic. The patients were studied as regard their full history and examination, and their psychological status was assessed using the Patient Health Questionnaire 9 (PHQ-9) before and after the rehabilitation program. Verbal consent was taken from each patient, confidentiality was ensured, patients were informed about findings in their results and they had the right to refuse inclusion Results The study included a majority of male patients: 51 male patients (85%) and 9 female patients (16.5%). The mean age was 52 years. 15% of the patients were diabetic and 40% hypertensive, 46.7% were smokers and 48.3% were dyslipidemic. There was no statistically significant correlation between age, gender and risk factors and whether or not the patients completed the cardiac rehabilitation program or dropped out. Most patients were presenting after anterior STEMI (63.3%) followed by inferior STEMI (21.7%) with a minority of NSTE-ACS patients (15%). There was a statistically significant effect of the CR on the CCS class but not on the NYHA class. The median PHQ-9 score before joining the program in the control group of 15.5, while that of the study group ranged from 8 to 20 with a median of 13, which was a significantly different score (P 0.03). Right after finishing the program the study groups PHQ-9 score median was 6.5. Three months after the beginning of the CR program the median PHQ-9 score was 23.5 and 0 for the control group. The change of the PHQ-9 over the course of 3 month from the beginning of the CR program was significantly improved for the study group with (P 0.00) and the median PHQ-9 score decreased from 13 to 0, while the control groups PHQ-9 score significantly deteriorated with a median score changing from 15.5 to 23.5. Conclusion CR is a highly effective method in reduction of the comorbid depression in coronary disease patient and should be recommended as a routine management after acute coronary events.