Resumo. The ectomycorrhizal fungi association with native forest essences could be an alternative to improve the adaptation and the development of seedlings in reforested areas of Rio Grande do Sul State. The aim of this work was to identify and to characterize the ectomycorrhizal associations in Apuleia leiocarpa and Peltophorum dubium seedlings, under laboratory conditions. Four inoculation treatments with ectomycorrhizal isolates were used to Apelui leiocarpa: UFSM RA 2.8 (Suillus sp.), UFSM RA 3.6, UFSCPt116 (Pisolithus microcarpus) and UFSC-Pt24 (Pisolithus sp.) and one uninoculated as control. For P. dubium, were used the isolates UFSM RA 2.8 UFSC-Pt116, UFSC-Sc124 (Scleroderma citrinum Pers.) and UFSC-Pt24 (Pisolithus sp.), and control. For both forest essences there were seven replicates per treatment. It was analyzed the following parameters: height of plants, fresh matter of shoots and roots, dry matter of shoots and roots and presence of ectomycorhizal colonization. Ectomycorrhizas were observed in Apuleia leiocarpa seedlings inoculated with the isolate UFSM RA 2.8 (Suillus sp.). This fungus also improved seedlings growth, as height of plants, fresh and dry matter of shoots, although, it was not statistically different from the other isolates. Seedlings of Peltophorum dubium presented evidences of ectomycorrhizal formation, like the presence of a fungal mantle.