This work was carried out under field conditions to study the biological control of European red mite, Panonychus ulmi (Koch) on apple trees in Dakahlia Governorate using the predacious mite Neoseiulus cucumeris (Oud.). The European red mite P. ulmi is considered one of the important mite pests attacking apple trees causing serious damage to leaves and fruits. The predatory mite was reared on the two-spotted spider mite Tetranychus urtica Koch and released at three levels. 50, 100 and 150 individuals per tree at average level infestation 5.65, 5.78 and 5.51 mite per leaf, respectively, while it was in control tree 8.92 individual per leaf. The reduction percent of P. ulmi population on apple trees reached 90.16 after four months from release at level of release 150 individuals per tree. The above mentioned results indicated the possibility of controlling the European red mite P. ulmi on apple trees using the predatory mite N. cucumeris as a biocontrol agent.