The scavenger receptor A-I/II (SRA-I/II) on alveolar macrophages is involved in recognition and clearance of modified lipids and inhaled particulates. A rare variant of the SRA-I/II gene, Arg293X, truncates the distal collagen-like domain, which is essential for ligand recognition. We tested whether the Arg293X variant is associated with reduced lung function and risk of chronic obstructive pulmonary disease (COPD) in the general population.