The study dealt with the issue of accurate diagnosis of COPD in older patients (over 65 years), where standard methods may not be optimal. A new ECDS diagnostic score (Elderly COPD Diagnostic Score) was developed, which integrates clinical and functional parameters. The ECDS includes weighted components such as FEV₁/FVC, age, Charlson comorbidity index, mMRC dyspnea score, and COPD Assessment Test score. The ECDS score demonstrated high accuracy in differentiating COPD from non-COPD in two cohorts of patients. The study also identified age-specific FEV₁/FVC thresholds that are more accurate than a fixed value. The ECDS represents a potentially useful tool for the diagnosis of COPD in elderly patients, especially those with comorbidities. Further verification is necessary for mild forms of the disease.