Destruction of lung elastin is critical for development of emphysema associated with chronic obstructive pulmonary disease (COPD). Lung macrophages release elastolytic enzymes, including matrix metalloproteinase (MMP)-9, along with tissue inhibitors of MMP (TIMP). We examined the production and activity of macrophage-derived MMP-9 and TIMP-1 from alveolar macrophages (AM) from smokers with COPD, healthy smokers (HS), and nonsmokers (NS). AM were stimulated with either lipopolysaccharide (LPS), interleukin (IL)-1 beta, or cigarette smoke-conditioned culture medium (CSM). AM from patients with COPD released greater amounts of MMP-9 with greater enzymatic activity than HS and NS. In contrast, AM from NS released more TIMP-1 than cells from HS and subjects with COPD. LPS and IL-1 beta caused a dose-dependent increase in MMP-9 release and activity, together with increased levels of TIMP-1. Dexamethasone prevented the increase in MMP-9 release, and increased TIMP-1 release. CSM increased MMP-9 and TIMP-1 release from AM of all groups. Dexamethasone decreased CSM-stimulated MMP-9 release, but had no effect on MMP-9 activity This study suggests that macrophages might be important in the development of COPD because these cells exhibit increased levels of elastolytic activity.