Background: Chronic Obstructive Pulmonary Disease (COPD) is a major cause of morbidity and mortality worldwide. Oxidative stress plays a critical role in its pathogenesis. Selenium, an essential trace element with antioxidant properties, is hypothesized to influence airway dysfunction in COPD. Objective: To assess the serum selenium level in COPD patients visiting a tertiary care hospital and compare it with age and sex-matched controls. Methods: This observational, hospital-based cross-sectional study included 29 COPD patients and 16 healthy controls. Serum selenium levels were measured using Atomic Absorption Spectroscopy (AAS) with a Flame Analysis method. Statistical comparisons were made between cases and controls using appropriate tests. Results: The mean serum selenium level was significantly lower in COPD patients (76 µg/L) compared to controls (108.38 µg/L). Additionally, selenium levels were influenced by smoking status, socioeconomic background, and occupational history. Active smokers exhibited lower selenium levels (57.43 µg/L) than non-smokers (88.03 µg/L). Lower socioeconomic groups and individuals with occupational exposures, such as carpenters and quarry workers, also had significantly reduced selenium levels. Conclusion: This study highlights an association between decreased serum selenium levels and COPD. Given selenium's role in antioxidant defense, its deficiency may contribute to disease progression. Further studies with larger sample sizes are needed to establish selenium as a potential biomarker for COPD and explore the benefits of selenium supplementation in disease management.