Background: Chronic obstructive pulmonary disease (COPD) is a major cause of respiratory morbidity and mortality worldwide. One of the main hypotheses concerning the pathogenesis of emphysema, a key cause of morbidity and mortality in COPD, is the protease antiprotease imbalance. Irreversible airflow obstruction in Chronic Obstructive Pulmonary Disease (COPD) is thought to result from airway remodeling associated with aberrant inflammation. This study examined changes in sputum as regards MMP-9, TIMP-1 and levels of inflammatory cells in COPD patients compared with sputum of healthy smokers and non smokers. Methods: Forty patients were included in this study. FEV1 before and after salbutamol inhalation, MMP-9, TIMP-1 and inflammatory cell count in the sputum of COPD patients, healthy smokers and non- smokers were investigated. Results: MMP-9 was significantly increased in both COPD patients (194.4± 100.6), and healthy smokers (104.5± 42.1) compared with healthy non smokers (34.5± 36.1). TIMP-1 was increased more in healthy non-smokers (192.7 ±37.7) than COPD patients (115± 55.5) and healthy smokers (145.3± 35.1). MMP-9/TIMP-1 was high in COPD patients (1.7 ± 0.9) and healthy smokers (0.7 ±0.3) compared with healthy non smokers (0.2 ± 0.2). Mean sputum total leucocytic count (TLC) was highly statistically significantly different between the three groups. COPD group showed the highest means value while non smokers group showed the lowest one. Conclusions: COPD is characterized by an imbalance between MMP-9 and TIMP-1 which may play an important role in the pathogenesis of tissue remodeling and airway obstruction.