Several types of associative microbes inhabit in the rhizosphere of legumes. These include plant growth promoting rhizobateria (PGPR) with a prominent place taken by N2-fixing bacteria (symbiotic and N-free fixing) and mycorrhizal fungi. Associations with these microbes play important role in the nutrition, development and yields of legumes. Whereas symbiosis with N2-fixing bacteria can mitigate the need for N fertilizer applications in soils where P availability is not a serious constraint, mycorrhizal symbiosis often can provide a more efficient mechanism for P uptake from the soil by plant roots. Stimulation of mycorrhizal symbiosis has the potential to improve yields and sustainability of agricultural production in the short term. However, it will require replenishment of soil P resources on a long run. Phosphate solubilising bacteria (PSB) possess the ability to solubilise insoluble inorganic P sources. Given the variety of functions, different microorganisms can synergistically interact with respect to improving legume yields. This appears particularly important in tropical soils, in Africa and Asia where yields remain very low and socio-economic constraints limit applications of expensive mineral fertilisers. Use of microbial inoculants tailored to local soil conditions thus present an alternative to sustainably improve yields and empower farmers in the short term. This paper aims to review results of several field inoculation trials using commercial inoculants and to raise some important issues such as product quality, role of plant genotype in the efficiency of microbial inoculations, formulation of commercial microbial inoculants including mycorrhizal fungi, and prospects to optimize crop responses to inoculation under field conditions. (Texte intégral)