Aspergillus fumigatus, the major cause of life threatening invasive aspergillosis (IA), is a ubiquitous saprophytic fungus to which humans are exposed daily in most parts of the world. The infection is initiated by inhalation of conidia, which are cleared quickly in a normal host but can cause invasive disease in immunocompromised individuals [1, 2]. The following features make A. fumigatus a ubiquitous pathogen: 1) survival and growth in a wide range of environmental conditions, 2) effective dispersal in the air, 3) physical characteristics that allow conidia to reach the distal airways, and 4) swift adaptability to the host environment. The biology, pathogenesis, molecular biology, and virulence factors of A. fumigatus have been exhaustively reviewed [2–8]. This brief article focuses on how A. fumigatus is equipped with the features necessary for a ubiquitous pathogen.