Effect of the predatory mite, Amblyseius swirskii Athias-Henriot on the population of melon thrips, Thrips palmi Karny was investigated on eggplant in greenhouses without a heater in 2009 in Osaka Prefecture. In the released plots in five places, 25-50 A. swirskii per square meter were released for control of the thrips once or twice from March to May, respectively. A. swirskii colonized on leaves and flowers, the population densities of the thrips became lower in the released plots than in the control plots after the releasing. The injury to eggplant fruits by the thrips became lower in the released plots than in the control plots. The results suggest A. swirskii is effective as an agent for controlling the thrips on greenhouse eggplant.