Abstract The objective of this study was to assess the efficiency of a mixed arbuscular mycorrhizal fungi (AMF) inoculum versus a single isolate to promote the seedling development of native Caatinga species: baraúna (Schinopsis brasiliensis Engl.) and juazeiro (Zizyphus joazeiro Mart.). The experiment was conducted in a greenhouse, presenting a completely randomized design with four treatments (Control - not inoculated, inoculated with Claroideoglomus etunicatum, Acaulospora longula or a mix of C. etunicatum and A. longula) and seven replicates. The AMF inoculation promoted an increase in all growth variables of the two plant species, with increments above 100% in all inoculation treatments, and a significant reduction in the transplanting time of the seedlings to the field. We concluded that the AMF use under study in the mixed form is as beneficial as in the isolated form for Z. joazeiro and S. brasiliensis seedling production.