Abstract: A wood preservative based on leaching-resistant, inorganic compounds for protection of wood and wood materials against wood-damaging insects and fungi, including wood-rot fungi, is disclosed. The wood preservative, which is fixed without chromium, contains as active ingredient in an aqueous solution which is stable on impregnation, (a) a Cu(II), Zn, Ni, Co, Fe, Mg and/or Mn salt of monofluorophosphoric acid, or (b) an alkali metal salt and/or ammonium salt of monofluorophosphoric acid, in the presence of a Zn, Ni, Co, Fe, Mg and/or Mn salt of hydrochloric, nitric or sulfuric acid and, optionally in addition to (a) or (b), one or more members of the group comprising NH.sub.3, HCl, HNO.sub.3, H.sub.2 SO.sub.4, HF, alkali metal hydrogen fluoride and ammonium hydrogen fluoride. Alternately, the composition contains (c) an alkali metal salt and/or ammonium salt of monofluorophosphoric acid in the presence of a Cu(II) salt of hydrochloric, nitric or sulfuric acid in a Cu.sup.2+ :PO.sub.3 F.sup.