Objective. Examining the effects of a pulmonary rehabilitation (PR) program applied to patients undergoing coronary artery bypass grafting (CABG) surgery with open heart technique on respiratory functions, functional capacity, and quality of life (QoL). Design. This randomised controlled study applied the Consolidated Standards of Reporting Trials statement. Methods. The study was conducted with two groups: the intervention group (n = 25) and the control group (n = 25). The control group received standard care after coronary artery bypass grafting. On the contrary, the experimental group participated in a PR program created by the researchers in addition to standard care. After coronary artery bypass grafting, the respiratory functions (on the 4th day of clinical care) and QoL (at the 6th week) of both groups were evaluated. The primary outcome measure was the respiratory function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC). The secondary outcome measure of this study was the QoL. Results. When the average pulmonary function test values of the patients were examined, the mean FVC and FEV1 values of the patients in the intervention group on the 4th day of clinical care were significantly higher with a medium level size effect than the control group (p = 0.027; effect size (d) = 0.643; p < 0.024; effect size (d) = 0.658, respectively). At the postoperative 6th week measurement of QoL, a decrease was observed in all subdimensions of the scale, albeit less in the intervention group (p < 0.05). There was a decrease in both the mental and physical component summary of QoL (p < 0.05). Conclusion. The results of this study revealed that pulmonary rehabilitation applied to patients who have undergone coronary artery bypass graft recover their functional capacity faster.