Abstract: This experiment was conducted to evaluate the combined effects of Citric Acid (CA) and Microbial Phytase (MP) on the serum concentration and digestibility of some minerals in broiler chicks. This experiment was conducted using 360 Ross-308 male broiler chicks in a completely randomized design with a 3x2 factorial arrangement (0, 2.5 and 5% CA and 0 and 500 FTU MP). Four replicate of 15 chicks per each were fed dietary treatments. The concentration of zinc, copper and manganese of serum and their digestibility and also digestibility of apparent metabolizable energy (AMEn) was evaluated. The results showed that interaction effect of CA and MP on concentration of copper, zinc and manganese in serum of broilers fed with low available phosphorus diets was significant (p<0.05). Adding 2.5% CA into low available phosphorus diets increased digestibility of zinc in comparison to diets without CA and with 5% CA in broiler. Adding CA into low available phosphorus diets increased manganese digestibility on based corn-soybean meal diets (p<0.01).