The invention relates to a method for producing lithium metal phosphates of a formula LiMPO4, wherein M is at least one type of bivalent metal, preferably selected from the first transition metal range. The inventive method consists in reacting a lithium phosphate with a metal salt and an acid phosphate source in a polar solvent for converting into a corresponding M-containing phosphate, in adding a basic lithium source for obtaining a precursor mixture for a desired lithium metal phosphate, in converting and separating the thus obtained mixture, preferably in hydrothermal conditions, in such a way that a desired final product is obtained, thereby receiving a lithium-containing filtrate. The addition of the basic lithium source initiates a lithium ion precipitation in the form of a lithium phosphate. The thus obtainable lithium phosphate can be reused in the form of a raw material, whereby said cycle enables lithium to be highly reusable.