The objective of this work was to evaluate the initial growth and biomass partitioning of mulungu (Erythrina velutina Willd.) seedlings under different rates of phosphorus in the presence and absence of arbuscular mycorrhizal fungi (FMA’s). A randomized blocks design in a 5 x 2 factorial arrangement was used, with four replicates and three plants per plot. Treatments consisted of five phosphorus rates (0, 50, 100, 150 and 200 mg.Kg soil^-1), using as source the superphosphate fertilizer, and presence or absence of FMA’s. At 98 days after sowing (DAS), shoot height, stem diameter, leaf number, leaf chlorophyll index, leaf dry matter, stem dry matter, root dry matter, leaf area, Dickson quality index and height/stem diameter ratio were evaluated. The phosphorus rate of 200 mg.kg^-1 proved to be the most efficient for production of Erythrina velutina seedlings, but with a significant reduction in the biological association of this plant with rhizobacteria. Biomass distribution within the different parts of the plants did not change with distinct rates of P, and there were no benefits in the use of FMA’s until 98 DAS.