Methods are described for the production of hydrogen-bis(chelato)borates of the general formula H[BL.sup.1L.sup.2] and of alkali metal-bis(chelato)borates of the general formula M[BL.sup.1L.sup.2] where M=Li, Na, K, Rb, Cs L.sup.1=--OC(O)--(CR.sup.1R.sup.2).sub.n--C(O)O-- or --OC(O)--(CR.sup.3R.sup.4)--O-- where n=0 or 1, R.sup.1, R.sup.2, R.sup.3, R.sup.4 independently of one another denote H, alkyl, aryl or silyl, L.sup.2=--OC(O)--(CR.sup.5R.sup.6).sub.n--C(O)O-- or --OC(O)--(CR.sup.7R.sup.8)--O-- where n=0 or 1, R.sup.5, R.sup.6, R.sup.7, R.sup.8 independently of one another denote H, alkyl, aryl or silyl, wherein the respective raw materials are mixed in solid form without the addition of solvents and are reacted. Lithium-bis(oxalato)borate, lithium-bis(malonato)borate, caesium-bis-(oxalato)borate, caesium-bis-(malonato)borate and the mixed salts lithium(lactato,oxalato)borate and lithium(glycolato,oxalato)borate for example may be produced in this way.