The aim of this work is to study the removal of nitrate from brackish polluted water using electrodialysis. The influence of several parameters, such as flow rates, initial feed concentration, co-existing anions and initial pH on process efficiency were studied. This efficiency is evaluated by the removal rate, demineralization rate and power consumption. The denitrification process showed to be independent of pH of feed solution. Although The flow rate as well as the initial salt concentration and also the coexisting anions on the feed solution play a significant role on the denitrification efficiency and mainly on the specific power consumption. The decrease of this parameter induces a decrease on the total energy needed to perform required operation. The denitrification of a contaminated real water sample was investigated so as to improve the efficiency of denitrification process. The nitrate concentration could be reduced from 225 to 25.5 mg L-1 (88% removal) which was lower than World Health Organization (WHO) standard (50 mg L-1). Moreover the concentrations of different species in the obtained treated water are below the amounts recommended by WHO for drinking water.