A study was conducted to investigate the effect of phytase on the AMEn of peanut meal. One hundred twenty Ross x Ross broiler chicks of mixed sex were fed one of 4 experimental diets from 5 to 15 d of age. Diets used were Diet 1, a low P corn-soybean based basal diet; Diet 2, a 50% basal + 50% peanut meal diet; Diet 3, the basal diet supplemented with 24,000 phytase units (FTU) of Natuphos 5000 phytase/kg; and Diet 4, a phytase-supplemented 50% basal + 50% peanut meal diet. Chromic oxide was added to the basal diet at 0.1% as an indigestible marker. Apparent metabolizable energy was determined by substituting peanut meal at the expense of the basal diet. Other parameters measured included the phytate content of the diets as well as phytate P disappearance. Phytase significantly improved phytate P disappearance for both the corn and soybean meal basal diet (23.8 to 93.7%) as well as the 50% basal + 50% peanut meal diet (16.7 to 89.5%). Phytase increased the AMEn of peanut meal on a DM basis by approximately 9%, from 3,209 to 3,559 kcal/kg.