The acaricidal activity using the recommended concentrations of the novel compound cyflumetofen 24% SC as compared with bifenazate 48% SC and abamectine 1.8% EC was determined against the two-spotted spider mite, Tetranychus urticae Koch under greenhouse conditions at Faculty of Agriculture, Cairo University during 2017-2018. Their side effect on the predatory phytoseiid mite, Phytoseiulus persimilis Athias-Henriot was also investigated. Average number of mite mortality in the two seasons showed that abamectin was more toxic to predatory mite than other tested acaricides, while cyflumetofen was more toxic to spider mites T. urticae and followed by abamectin and bifenazate. Field trials proved that cyflumetofen was not as harmful as other compounds. Therefore, life-table parameters of both T. urticae and P. persimilis treated with LC₅₀ of cyflumetofen were investigated in laboratory to know more knowledge about the population growth of mite pest and its natural enemy under stressful of treatment. Cyflumetofen prolongedthe mean generation time, doubling time while it decreased fecundity as represented by female proportion in the generation, net reproductive rate, intrinsic rate of increase, finite rate of increase and gross reproductive rate of both mite species. Cyflumetofen showed considerable negative effects on T. urticae life-tables but it had moderate or low effects on P. persimilis. It is recommended to use the novel acaricide, cyflumetofen in IPM programs of plants feeding spider mites.