It is shown that the oxygen-stabilised compounds Zr 3 Fe(Co)O x (x = 0-1.0) interact with hydrogen at ambient temperature and pressure forming saturated hydrides with filled Re 3 B type structure. The hydrogen storage capacity decreases with increasing oxygen content from 6.7 H/f.u. for Zr 3 Fe down to 5.35 H/f.u. for Zr 3 FeO 1 . 0 and from 6.9 H/f.u. for Zr 3 Co down to 5.3 H/f.u. for Zr 3 CoO 1 . 0 . A small change of the unit cell volumes for the Zr 3 Fe(Co)O x parent compounds and a substantial increase of these parameters for the corresponding saturated hydrides were observed with increasing oxygen content. The partial hydrogen-induced lattice expansion, ΔV/at. H, increases from 2.25A 3 for Zr 3 FeH 6 . 7 up to 3.38A 3 for Zr 3 FeO 1 . 0 H 5 . 3 5 and from 2.08A 3 for Zr 3 CoH 6 . 9 up to 3.25A 3 for Zr 3 CoO 1 . 0 H 5 . 3 . Rietveld refinement using neutron powder diffraction data for Zr 3 FeO 0 . 4 D 6 . 2 5 showed a distribution of deuterium atoms and a redistribution of oxygen atoms from octahedral to tetrahedral sites in a similar way as in Zr 3 NiO x D y . Both 5 7 Fe Mossbauer spectroscopy and magnetic susceptibility measurements of Fe-containing hydrides indicated weak hydrogen-induced magnetic ordering at low temperatures. The ordering temperatures of Zr 3 FeO 0 . 2 H 6 . 5 2 and Zr 3 FeO 0 . 6 H 6 . 2 5 are 105 and 140K, respectively.