Resumo. The inoculation of mycorrhizal arbuscular fungi (FMAs) is viable in forest species. The aim of this study was to evaluate the establishment of two species of FMAs, in Acácia mearnsii production, considering different substracts and phosphour levels. The experiment was carried out with five treatments, with two species of FMAs (Glomus clarum Nicolson & Schenck and Glomus etunicatum Becker & Gerdemann), and three kinds of substracts (Mecplani, Fertil Turfa and Neossolo Quartzarênico) with four phosphour levels, with 10 repetitions. The high level of P in the substract did not influence the mycorrhizal colonization in the roots. These mycorrhizal fungi showed high efficiency in roots colonization of A. mearnsii. The Mecplani and Fertil Turfa substracts were the most efficient ones in seedling growing.