Iron oxides and hydroxides are reactive soil components that can largely control soil P sorption. Our objective was to quantify the sorption of inorganic P and three organic P compounds (adenosine triphosphate, glucose 6 phosphate, and inositol hexaphophate) by both ferrihydrite and goethite. The P compounds were added either individually (noncompetitive) or in combination with each other (competitive) using 24 hour sorption isotherms. The results and implications of this study will be presented in this poster.