Around 41% of the world’s population continue using solid fuels, including wood and other types of biomass, for cooking or heating their homes. Long-term indoor exposure to wood smoke, and biomass smoke in general, is a risk factor for developing chronic obstructive pulmonary disease (COPD). In some regions of the world, biomass exposure is a more frequent cause of COPD than exposure to cigarette smoke. Recently it has been described notable differences between COPD associated with wood smoke (WS-COPD) and that caused by tobacco smoking (TS-COPD): significantly less emphysema and more airway inflammation in WS-COPD. Recognizing these differences, some authors have suggested that WS-COPD should be considered a new COPD phenotype. This chapter summarizes the differences between WS-COPD and TS-COPD. The information about the characteristics of COPD caused by other types of biomass fuels, different from wood, is very scarce. Accepting that the smoke derived from wood burning and tobacco smoking have some differences (etiology), the inhalation patterns are different (pathogenesis) and the physiopathological mechanisms they induce may also differ, we analyze if the disease caused by indoor chronic exposure to wood smoke should be considered as another COPD phenotype or a distinct nosological entity.