In the last quarter of century, the analysis of small airways specimens obtained from chronic obstructive pulmonary disease (COPD) patients compared with those from a control group of age-matched smokers with normal lung function has provided novel insights on the potential role of the different inflammatory and structural cells, pro/anti-inflammatory mediators and intracellular signalling pathways, contributing to a better knowledge of the pathogenesis of stable COPD. This also has provided a scientific rationale for new drugs discovery and targeting to the small airways. This review summarizes and discusses the pathology of small airways of stable COPD patients, of different severity, compared with control smokers with normal lung function.