Magnetic susceptibility and powder neutron diffraction results are reported on the cubic spinel Co2RuO4. These measurements indicate spin-glass formation in this compound, with a freezing temperature of about 16 K. Magnetic susceptibility results are also reported on ZnCoRuO4, a spinel in which only the Ru3+ ions are magnetic. No magnetic order was found in ZnCoRuO4 down to 2 K, indicating extremely weak interactions between the octahedral Ru3+ ions in these materials.