AbstractThe ecological functions of soil fauna have attracted widespread interest from ecologists during the past two decades. A growing number of evidences show that the soil fauna interact with microorganisms and play important roles in regulating soil ecosystem processes and plant growth. This review addresses the issue of how bacterial- and fungal-feeding nematodes influence soil microorganisms, nitrogen mineralization and plant growth. Most studies suggest that bacterial- and fungal-feeding nematodes stimulated soil nitrogen mineralization and promoted plant growth. The mechanisms underlying these effects are the impact of nematode grazing on microorganisms and the release of nutrients from consumed microbial biomass. How-ever, these effects vary with different nematode species, microorganism species, plant species and C/N ratios of substrates, and are influenced by complex interactions between different trophic groups of nematodes as well as other soil fauna. Future studies should (1) enhance our understanding about the mechanistic basis of the interaction of nematodes, microorganisms and plants; (2) address more complex interactions between different trophic groups of nematodes and other soil fauna; (3) examine the ecological roles of soil nematodes at a longer temporal scale; (4) compare different ecosystems to understand the ecological roles of soil nematodes at a broader spatial scale; and (5) predict the responses and feedbacks of soil nematodes to atmospheric drivers of global changes.