Background: The incidence of postoperative pulmonary complications (PPCs) following coronary artery bypass grafting (CABG) is between 30% and 60% and are the most significant contributor to morbidity, mortality, and expenses associated with the hospitalization. Chest physiotherapy is the fundamental component in post-operative physiotherapy. This study will specify the preferable technique for early prevention of postoperative pulmonary complications. Objective: The study aims at comparing the immediate effects of deep breathing with acapella and incentive spirometer in preventing early postoperative pulmonary complications followed by CABG. Method: In this study, 30 subjects fulfilling criteria divided into group A and group B randomly. Group A received breathing exercises with acapella and group B with the incentive spirometer. The outcome was evaluated through SPO2 levels, peak expiratory flow rate (PEFR), and numerical rating scale scores for dyspnea (NRS). The data was analysed and the inference was drawn through paired and unpaired t-tests. Results: The study obtained very discrete findings. Out of 4 days recordings of the outcome, the SPO2 levels were significantly improved in group B than group A on the first day of treatment, while after 4days of treatment there was no significant difference between group A and group B. The PEFR score was significantly higher in group A than group B after four days. There was no significant difference in the lowering of NRS score for perceived shortness of breath among both groups. Conclusion: In this study it is concluded that the breathing exercises through Acapella and Incentive Spirometer are effective in preventing early PPCs followed by CABG by improving PEFR(mostly through acapella), SPO2 levels and reduction of shortness of breath, thus improving quality outcome.