Fusarium culmorum and F. equiseti were characterized with regard to production of trichothecenes and other secondary metabolites. Results following growth on laboratory media are interpreted with the aim of increasing the understanding of fungal metabolism in the field environment. While trichothecene production was detected for 94 of 102 F. culmorum isolates, only 8 of 57 F. equiseti isolates were positive. Profiles of secondary metabolites were compared by following growth on yeast extract sucrose agar (YES), potato sucrose agar (PSA), and an agar medium, prepared from soil organic matter (SOM), which was included to simulate growth conditions in soil. SOM supported the production of chrysogine by F. culmorum. The two species utilized the media differently. F. culmorumproduced zearalenone (ZEA) on YES, whereas some F. equiseti isolates produced ZEA on PSA. Other F. equiseti isolates produced equisetin. These differences may reflect that F. culmorum depends on a pathogenic life style while F. equiseti has a more saprotrophic mode of existence.