Introduction : Chronic obstructive pulmonary disease common is very in smoker and old age . Infection is common cause of acute exacerbation of COPD. It increases morbidity and day of stay of admitted patients in hospital. Our study purpose is to identify causative microorganism and sensitivity pattern of isolates. Material &methods : This is retrospective study, done in COPD patient admitted in hospital . Sputum sample collected aseptically, culture done on blood agar and Mac Conkey`s agar. Positive cases obtained on culture were included in this study. Isolates were identified by standard bacteriological protocol as per CLSI guideline. Result: Out of 100, 60 bacterial isolates recovered from sputum sample, commonly isolated species are Klebsiella pneumonia, , Staphylococcus aureus ,Pseudomonas spp, E.coli, and Acinetobacter baumanii. Conclusion: To decrease morbidity and hospital stay in COPD patients, early diagnosis and initiation of appropriate treatment of patients is necessary.