The extraction of essential oils from natural sources is a highly profitable now a days.rnVetiver grass is a viable vegetative absorbent and erosion barrier; in addition the valuablernoils extracted from its roots are playing an increasing role in the perfume, food andrnpharmaceutical industriesrnThe yield of essential oil that extracted from the vetiver grass root depends strongly onrnextraction parameters and method of extraction such as time, temperature and particlernsize are vital components for efficient processing of essential oil extraction. Thernexperimental investigations undertaken using steam distillation has been determined arnmaximum average yield of (1.72%) after extraction time of 6 hours, particle size range ofrn(0.425-0.75mm) and temperature of (95oC) and the minimum average yield was obtainedrn(0.15%) was found at extraction time of 2hr, temperature of (75oC) and particle size ofrn(1.075-1.4mm). From this statement, an increasing of extraction time, temperature andrndecreasing of particle size will increase the percentage yield of oil extract. Therninvestigating of individual and interaction effect has been described by using excel graphrnand DESIGN EXPERT software (general full factorial) was applied to the extractionrnprocesses.rnThe composition of the vetiver oil extracts were analyzed using gas chromatographymassrnspectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR)rntechniques and this showed that, a high percentage was obtained ((3S, 3aR, 6R, 8aS)-7,rn7-dimethyl-8 methyleneoctahydro-1H-3a,6-methanoazulen-3-yl) methanol in a peakrnretention time of (16.780min) and high percentage of area was obtained (23.37%).