Single-phase complex oxides Nd2-yCayCoxNi1-xO4 have been synthesized for the first time. Composites prepared by the reduction of these compounds with hydrogen and containing Nd2O3, CaO, and cobalt and nickels metals have been used for the first time as catalysts of the partial oxidation of methane. The maximal methane conversions (97%) and syngas yields (96%) at 900 °С have been detected in the presence of the composite obtained from Nd1,5Ca0,5NiO4. At T < 850 °C, the nickel–cobalt composite synthesized from Nd1,3Ca0,7Co0,4Ni0,6O4 turned out to be more selective in the formation of syngas. Decreasing the partial oxidation temperature from 900 °С to 750 °С leads to the oxidation of metallic nickel and cobalt to oxides and to partial resynthesis of complex oxides with perovskite and K2NiF4 structures. The observed differences in temperature dependence of the catalytic properties of composites with various Ni/Co ratios can be associated with the participation of complex oxides in catalysis of the partial oxidation of methane at low temperatures.