Manipulation of animal diets can reduce manure phosphorus (P) in areas where animal production is intensified. Solubility of swine manure P in soils amended with phytase will provide information on what changes occur in manure P with time. Manure samples were collected from 28 growing pigs fed randomly with seven dietary treatments at different levels of phytase. The seven treatments were: A positive control (NRC) that contains P at NRC (1998) recommendations, a negative control (RED)  containing 0.1 percentage units reduction (about 33%) in available P from 1998 NRC recommendations, RED + PHY1 (RED plus 500U of phytase / kg of diet), RED + PHY2 (RED plus 1000U of phytase / kg of diet), a double negative control with no added inorganic P (DNC), DNC + PHY3 (with 2000U of phytase / kg of diet), and DNC + 4000U of phytase / kg of diet). Manure (feces+urine) from 4 replicates of each treatment were mixed to form a composite and the total P determined. This manure was added to four Manitoba soils to provide total P of 75 kg P ha^-1. The soils were incubated in four replicates at field capacity water content for 1, 4, 16 wks at 20⁰C and then extracted using H₂O, NaHCO₃, Kelowna and Mehlich-3 solutions for extractable P. The results obtained will be presented and discussed.