Background: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity in the elderly population. COPD leads to a reduced health-related quality of life (HRQL), but the factors which contribute to this are not well understood. A better understanding of the factors which determine HRQL should lead to an improved care for such patients. Objectives: The purpose of this study was to investigate possible age-related differences in HRQL in a population of patients with a similar severity of obstruction. Methods: A total of 180 consecutive COPD patients were enrolled into the study. We analyzed spirometric data, BODE index and its components, and comorbidities were assessed by the Charlson index. HRQL was assessed by the Clinical COPD Questionnaire (CCQ) and St. George's Respiratory Questionnaire (SGRQ). Results: The cohort consisted of 93 'younger' patients (mean age 54.8 ± 3.1 years) and 87 older patients (mean age 73.1 ± 5.5 years). Patients in both groups had a similar severity of obstruction: FEV₁ (% from predicted) was 39.9 ± 13.2% in the elderly group compared to 41.7 ± 11.7% in the younger group (p > 0.05). The forward stepwise regression analysis shows that the BODE index, the Charlson index, and the rate of exacerbations are important predictors of deterioration of HRQL in elderly COPD patients, which explains 29% of the total SGRQ score. In the younger COPD patients, the coefficient of determination R² was 0.27, but the predictors were the BODE index and the rate of exacerbations. Conclusions: The BODE index, the Charlson index, and the rate of exacerbations were found to be the major determinants of HRQL in elderly COPD patients, while in younger COPD patients, the BODE index and the rate of exacerbations were influential factors.