A two-stage desalination process is proposed for mineralized water with a salt content of >8 kg/m(3) in order to improve economical efficiency of the electrodialysis (ED) technique. The first stage involves ED desalination of the initial water in the galvanostatic regime at increased current density; the liquor is obtained with the salt content which is limiting for this method, and the dialyzate with the residual salt content allowing to avoid membrane polarization. The second stage involves profound desalination of the dialyzate in the potentiostatic regime resulting in desalinated water and the concentrate that is mixed with the initial water. For the mineralized water from the Tyumen' region, two-stage ED desalination and water preparation were investigated. A two-stage desalinating installation was developed and tested under industrial conditions; a model technological scheme of the industrial installation was developed for the complex processing of mineralized water from the oil and gas industry of western Siberia.