The purpose of the work is to study the adsorption of phosphate on red mud from aqueous solutions using 2 3 full factorial designs. The important parameters, which affect the removal efficiency of phosphate and final pH of solution (pH f ), such as phosphate concentration, initial pH of solution (pH i ) and the red mud dosage were investigated. The effects of individual variables and their interaction effects for dependent variables, namely, phosphate removal efficiency and pH f were determined. The results of the study showed that phosphate removal efficiency and pH f were found to be 97.6% and 10.9 with optimal reaction conditions initial phosphate concentration 25mgl −1 , red mud dosage 1.5gl −1 , pH i 3.0, respectively. It was found that adequate amount of calcium ions and higher final pH than 9 are ideal conditions for maximum phosphate removal.