Aspergillus fumigatus is the most important pulmonary fungal pathogen. Virulence has evolved several times in the section Aspergillii. However, there are species in this section, such as A. fischerii and A. oerlinghausensis, that are very closely related to A. fumigatus but are not reported as pathogens. By using trypsin shaving, we have identified the proteins on the conidial surface of conidia and swollen conidia of A. fumigatus, A. fischeri, A. oerlinghausensis, and A. lentulus. We have identified about 900 proteins in all four species and shown 52 that are unique in A. fumigatus. Both A. fischerii and A. oerlinghausensis have homologues for most of these proteins. However, they are not expressed in the conidia and and could reflect specific A. fumigatus traits important for infection and/or immune evasion.