Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is an acute event characterized by a worsening of the patient’s respiratory symptoms that is beyond normal day-to-day variations and leads to a change in medication. Exacerbations of COPD are caused by various factors such as viruses, bacteria, and possibly common pollutants. The study is conducted to know the bacteria predominantly causing the acute exacerbation of COPD in our region. Methods: A prospective observational study was conducted among 180 patients, admitted to the pulmonology department of a tertiary care hospital. Bacterial infections of AECOPD were analyzed. The sputum samples were subjected to culture study. Results: About 42.77% of cultures were positive for pathogenic bacteria. Among the pathogenic bacterial growth, the most common pathogenic bacteria isolated in sputum culture was Klebsiella pneumoniae, followed by Pseudomonas aeruginosa, Acinetobacter, Haemophilus influenzae, E. coli, Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis.