The conditions were found and the patterns of formation of Ni and Cu composites based on MgO, obtained by the precipitation method and by the glycine-citrate-nitrate method. The obtained materials are of interest as sorbents for the purification of aqueous media from toxic impurities, as well as catalysts in organic synthesis, in particular for the production of methanol from carbon dioxide. The phase composition, thermal stability, microstructure of obtained nanocomposites, as well as their sorption properties, were studied. It was found that high sorption capacities of powders of magnesium oxide and MgO-M (where M-Cu, Ni) nanocomposites with respect to lead and chromium ions are up to 2989.0 and 499.9 mg/g, respectively.