Phytic acid is the main storage form of P in grains and seeds. Cereals and grain legumes that are commonly used as poultry feed ingredients have similar phytate levels, approximating 0.25 percent of dry matter (Ravindran et al., 1995). There is not enough phytase activity in the digestive tract of chickens to digest phytate (Maenz and Classen, 1998). Phytate contributes to environmental pollution by reducing mineral and N bioavailability. The capacity of phytic acid to bind minerals reduces the utilization of P, Ca, Zn, Fe and N from plant ingredients by chickens (Sell et al., 2000). Phytate may form complexes with proteases, such as trypsin and pepsin in the gastrointestinal tract (Singh and Kricorian, 1982). These complexes may reduce the activity of digestive enzymes with a subsequent decrease in the digestibility of dietary proteins. It has been reported that microbial phytase improves the utilization of amino acids (Ravindran et al., 1999) and minerals in broiler chicks. The objective of the present study was to evaluate the effect of microbial phytase on the apparent digestibility of amino acids (AA) and some minerals in the diet of female broiler chickens.