Abstract Carbohydrase activity was analysed in 49 species of oribatid mites and one acaridid mite sampled from natural populations. Enzyme activity was determined for the main differentiating food components: cellulose, a component of cell-walls of green plants; chitin, a component of fungal cell-walls; and trehalose, a component of fungal cell-contents. Feeding guilds were defined based on the activity of the three carbohydrases. The nomenclature of the feeding guilds was adopted from that of ruminants. Five major feeding guilds were distinguished: herbivorous grazers (9 species), fungivorous grazers (8), herbo-fungivorous grazers (16), fungivorous browsers (7) and opportunistic herbo-fungivores (8) and two minor guilds in oribatids: herbivorous browsers (1) and omnivores (1). The feeding guilds presented are operationally better defined in terms of resource exploitation than the macro-, micro- and panphytophages used hitherto.