With respect to the need of very pure tetrapropylammonium hydroxide (TPAOH) in the synthesis of zeolites optimization was carried out of the preparation of an aqueous solution of TPAOH from tetrapropylammonium bromide by ion exchange on Amberlite IRA-401. A dependence of the yield and of purity of TPAOH on the starting concentration of TPABr was found and on the relative load of the anex. Under optimal conditions a yield of about 98 % was reached and the ratio of mass quantities is OH- : Br- = 1.4.103.