Background: Chronic Obstructive Pulmonary Disease (COPD) is a prevalent cause of morbidity and mortality worldwide, often accompanied by cardiovascular complications. Microalbuminuria (MAB) is considered a marker of systemic endothelial dysfunction and may serve as an early indicator of cardiovascular risk in COPD patients. This study aims to determine the prevalence of microalbuminuria in stable COPD patients and its correlation with pulmonary function parameters. Methods: A cross-sectional study was conducted on 139 stable COPD patients at GSL Medical College. Participants were selected based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Pulmonary function tests (PFTs) were performed using spirometry, and the urine albumin-to-creatinine ratio (UACR) was measured to assess microalbuminuria. Statistical analyses included correlation tests to evaluate the relationship between microalbuminuria levels and PFT parameters such as FEV1, FVC, and FEV1/FVC ratio. Results: Microalbuminuria was present in 29.5% of COPD patients. There was a significant correlation between microalbuminuria levels and COPD severity as defined by the GOLD staging system (p < 0.001). Patients in GOLD stages III and IV showed higher mean UACR values, indicating more severe endothelial dysfunction. However, no significant association was found between smoking history (pack-years) and microalbuminuria levels (p = 0.83). Conclusion: Microalbuminuria is prevalent in COPD patients, particularly in those with more severe airflow limitation. The significant correlation between microalbuminuria and PFT parameters suggests that MAB could be used as a non-invasive biomarker for assessing disease severity and cardiovascular risk in COPD patients. Early detection of microalbuminuria may help in the stratification and management of high-risk patients to prevent cardiovascular complications.