A greenhouse experiment was conducted in Babcock University, Ogun State, on sandy loam soil, from February to March, 2011, to assess the effect of Arbuscular Mycorrhizal Fungi (Glomus mosseae) and poultry droppings (PTD) on the growth and yield performance of Amaranthus as well as to evaluate the uptake level of phosphorus in Amaranthus plants. There were seven treatments laid out in a completely randomized design with three replicates. The AMF and PTD were applied into 3kg soil each at the rate of 5, 10, and 15g/pot each while the control had 0kg/pot. The plants treated with 10g/pot of mycorrhizal fungi produced the highest number of leaves (20) and least number of discolored leaves per plant (1.33) at five weeks after planting (5WAP). This yield was significantly higher than other treatments. From the results of this experiment, it can be concluded that 10g/pot is the optimum level of AMF fungi needed for Amaranthus cultivation above which to a waste or below which to insufficiency. The results of post soil analysis revealed that phosphorus rate reduced in all the AMF treated pots while all PTD treated pots had increased rate of phosphorus than the pre-planting soil values. The success of the improved yield of 10g AMF treated plants was achieved due to reduced P toxicity.