Coronary artery bypass grafting (CABG) often causes physiological changes in patients. Although functional changes, such as lung function and exercise capacity changes, are observed in patients, there are no detailed studies examining this. The aim was to compare preoperative and postoperative pulmonary function and exercise capacity in patients undergoing on-pump CABG with a multidimensional index (BODE index). Demographic and surgical characteristics of patients were recorded. Pulmonary function test, six-minute walk test (6MWT), and modified Medical Research Council (mMRC) dyspnea score were assessed and BODE index were calculated in preoperative and at six months postoperatively. A total of 75 patients were included with a mean ± standard deviation age of 59.8±10.0 years. The male to female ratio was 57/18. There was a statistically significant decrease in the forced expiratory flow at 25-75% (FEF_25-75%) value after CABG. Other pulmonary function test values were also lower in the postoperative period compared to the preoperative period, but these changes were not significant. The mean distance achieved in the 6MWT (p=0.02) and the mMRC dyspnea score (p=0.001) were significantly better postoperatively. The BODE index, which combines these parameters, had increased in the postoperative period. Age (OR 1.09; 95% CI: 1.008-1.181) and postoperative FEF_25-75% (OR -0.96; 95% CI: 0.938-0.988) were the independent predictors of BODE score ≥3 in multivariate analysis. Despite the decrease in pulmonary function in patients undergoing CABG, there was an improvement in exercise capacity and dyspnea score.