Water quality concerns associated with excess phosphorus in areas of concentrated broiler production have driven the use of broiler feed additives such as phytase. However, questions persist as to the effectiveness of these methods at reducing the environmental risk associated with phosphorus in the resulting litter. Furthermore, little is known about the effect of phytase on litter phosphorus during storage, prior to land application. The objective of this study was to evaluate the effect of dietary phytase and storage conditions on phosphorus forms in broiler litter. Three flocks of broilers were grown out on diets employing two levels of non-phytate phosphorus, with and without phytase. After removal of the third flock litter was collected from each diet and stored for 440 d. Litter water soluble phosphorus was measured throughout storage. In addition, litter phosphorus forms were evaluated before and after storage using ³¹P NMR and sequential chemical extractions. The results of this study will be reported.