Hydrodistillation has been employed for the extraction of essential oil from the leaves of patchouli plant. The yield of patchouli oil is dependent on solid loading, water volume, size of leaves and extraction time. The optimization of the process parameters has been performed using the Taguchi method while analysis of variance is used to identify the impact of parameters on the yield. The highest yield of patchouli oil (1.53%, w/w) is found at 30 g of solid loading, 900 mL of water volume, 4 mm size of the leaves and 150 min of extraction time. Among the parameters studied, extraction time had a greater impact on the yield of patchouli oil. Amount of patchoulol is maximum (64.9%) in the essential oil obtained under optimized conditions, thus, providing better quality of the essential oil.