For microfungi, the understanding of the extent of their biotic diversity and of their ecological function remains underdeveloped. An insufficient number of specialists are available to collect and document the world's microfungi. Organizations that exploit microfungi as a source of chemical products or for biotechnological applications also may need to assess microfungal diversity to meet their specific objectives. During future inventories of biomes that are deemed of high biological interest or that may harbor species of commercial potential, methods for enumerating microfungi must be made more efficient, and fungal communities should be evaluated in such a way as to extract the maximum information. Rapid isolation techniques can be used to deliver high species diversity and obtain quantitative estimates of fungal species diversity and abundance. These methods, some previously developed by soil ecologists, rely heavily on selective media, dissection, physical and chemical elimination of contaminants, knowledge of spore behavior, and manipulation of incubation conditions. The rapid expansion of our knowledge of endophytes in woody plants exemplifies the success of this approach. Whenever rigorous isolation strategies have been applied to unstudied substrates, an unrealized depth of species diversity has been revealed. When methods are standardized, richness of different fungal communities, geographic variation within communities, or effectiveness of isolation procedures can be quickly and quantitatively compared. Exploration of complex substrata via indirect isolation expands the view of the fungal community in a way that complements traditional mycological collecting. However, fungi isolated into culture are often impossible to identify based on morphology. The utility of the rapid isolation approach to the inventory problem is illustrated with experiences with microfungi from rain-forest leaf litter.Key words:fungal metabolites, industrial microbiology, microbial diversity, natural products.