Of the microorganisns that parasitize or prey on nematodes or reduce nematode populations by their antagonistic behaviour, fungi hold important positions and some of them have shown great potential as biocontrol agents. Fungi continuously destroy nematodes in virtually all soils because of their constant association with nematodes in the rhizosphere. A large number of fungi are known to trap or prey on nematodes but the most important genera include Paecilomyces, Verticillium, Hirsutella, Nematophthora, Arthrobotrys, Drechmeria, Fusarium and Monacrosporium. Application of some of these fungi has given very interesting results. There is an urgent need to develop some easy technologies for formulation and mass production of fungi at a commercial scale for field application. Some of these fungi may be used in integrated nematode management programmes despite some obstacles. Copyright (C) 1997 Elsevier Science Ltd.