The chemical constituents of the essential oil of lemongrass, Chymbopogon citratus that collected from Sharquia Governorate, Egypt, were determined by       GC-MS analysis. Geranial and neral were the basic constituents in the essential oil that recorded (48.692 and 34.137%, respectively). Moreover, the acaricidal and repellent activity of the essential oil were evaluated against T. urticae under laboratory conditions. According to LC₅₀ and LC₉₀, the lemongrass oil was more toxic against adults of T. urticae using spraying method than leaf dip technique method (direct feeding). Moreover, all the tested concentrations of the essential oil significantly reduced hatchability percentages of T. urticae eggs than control, that recorded (85.33 ± 3.72, 77.33 ± 3.76, 57.33 ± 3.59 and 33.33 ± 3.01%) for (0.25, 0.50, 1.00 and 2.00 %, respectively). Control gave 96.00 ± 0.00%. Also, the higher used concentration of lemongrass oil, recorded the highest significant repellency percentages against adults of T. urticae (79.96 ± 3.44%). While the lower one gave the least significant decrease (46.32 ± 2.61%).