The study compared 89 patients, 42 of them after coronary artery bypass surgery (CABG) and 47 with chronic obstructive pulmonary disease (COPD). Both groups were similar in age and sex, but patients after CABG had a higher body mass index (BMI) (p = 0.002). Patients after CABG achieved better overall scores in the St. questionnaire. George's Respiratory Questionnaire (SGRQ), including symptom and activity domains (p < 0.05). Lung function tests were also better in the CABG group: higher FVC (%), FEV1 (%) and FEV1/FVC ratio (all p < 0.05). Lower (ie, better) SGRQ scores were strongly associated with better lung function. Multiple linear regression showed that group type (CABG vs. COPD) was the only significant predictor of both FEV1 (%) (β = −0.25, p = 0.032) and total SGRQ score (β = 0.29, p = 0.016). The authors conclude that patients after CABG have more favorable lung function and respiratory quality of life than patients with COPD, and both groups require targeted rehabilitation and multidisciplinary management.