Chaetomium globosum is in the Kingdom Fungi (Mycota), Phylum Ascomycota. Although C. globosum is a soilborne fungus, it also commonly infests water-damaged buildings. The hyphae and ascospores can be highly allergenic. C. globosum isolates found in buildings and homes were investigated to determine their halotolerance response to various salts. Malt extract agar (MEA) or broth was amended with either NaCl, KCl, CaCl₂, or MgCl₂ at concentrations from 0 to 2 M. Ascospore germination, ascospore synthesis, vegetative growth (hyphal), and perithecia development were measured. C. globosum ascospore germination was inhibited by 1 M NaCl-amended media, but not by 1 M KCl-amended media. Ascospore synthesis and vegetative growth were inhibited when grown in 1 M KCl, 1 M NaCl, 1 M MgCl_2, and 1 M CaCl₂-amended media. However, 100 mM CaCl₂-amended plates inhibited ascospore synthesis. Growth of C. globosum in broth cultures showed similar growth patterns in salt-amended media. Perithecia synthesis was inhibited at 1 and 2 M concentrations of NaCl and KCl. Extracellular protein content was not different in the 0-100 mM treatments. However, extracellular protein synthesis as an indicator of vegetative growth and metabolic stress activity, was less in the 1 M NaCl-amended broth, and 7 to 10-fold lower in the 2 M NaCl-amended broth treatments. C. globosum isolates appeared to be halotolerant and only relatively high concentrations of salt inhibited the growth, ascospore synthesis, germination, and perithecia production. This research may have applications in controlling indoor mold growth and further the understanding of halotolerance in Chaetomium spp.