Magnetic susceptibility and magnetic hysteresis measurements were performed for Y2Ru2O7and Lu2Ru2O7, which show magnetic transitions at 80 and 85 K, respectively. Below the transition temperatures, there is a large difference in the temperature dependence of the magnetization measured between under zero-field cooled condition and under field-cooled condition, but no magnetic hysteresis has been observed. These results suggest that below the temperatures, both Y2Ru2O7and Lu2Ru2O7transform to a spin-glass state which is independent of the applied magnetic field. © 1999 Academic Press.