Arsenic and phosphorus are similar in chemical properties and compete with each other for sorption sites in soil. Effect of phosphorus on adsorption of arsenate in yellow-brown soil was evaluated in a batch experiment. Solutions different in P concentration were also used to extract As from the As contaminated soil. The results showed that when P concentration was low, the rise in P concentration might significantly reduce As adsorption but increase As extraction from the soil. When P concentration further increased, the changes in As adsorption and desorption became not so distinct. Sorption of As (V) even in the presence of high concentrations of P may be attributed to presence of sorption sites specific for As (V) and P and other sites that are common for both. Results of this study indicate that application of phosphate-containing fertilizer to As-contaminated soils may increase soil As solubility, phytoavailability and potential of leaching to groundwater.