An improved method for essential oil extraction was developed with the application of ohmic heated hydro distillation. In this study the parameters affecting citronella oil extraction by ohmic heated hydro distillation such as power input, extraction time, solvent to solid ratio and chopping frequency were investigated to achieve maximum oil yield. The kinetics of extraction was assumed and verified based on a second-order mechanism. The initial extraction rate, the saturated extraction capacity and the rate constant of extraction were calculated using the second-order model. The optimum parameters were found at voltage input of 77 V up to boiling point and 50 V until the end of extraction, 120 minutes extraction time, solvent to solid ratio of 3:1 and once chopping frequency. The kinetics and mechanism of ohmic heated hydro distillation of citronella oil has proved follow second-order model. The initial extraction rate (h) was 0.134 gL-1 min-1 ; the extraction capacity (C s) was 5.787 gL-1 ; the second order extraction constant (k) was 0.004 Lg-1 min-1 and the coefficient of determination (R 2) was 0.976. Index Terms-Ohmic heating; hydro distillation; citronella oil; optimization; kinetics I. INTRODUCTION Citronella grass is native to India and Sri Lanka; whereby the plant can be found growing wild in most tropical Asian countries including Malaysia. Citronella belongs to the genus Cymbopogon, which very closely resembles and formerly was included in the genus Andropogon [1]. Cymbopogon, which is native to warm temperate and tropical regions of the Old World and Oceania, is a genus comprising about 180 species, subspecies, varieties and subvarieties [2]. The plant is also growing wild in most tropical Asian countries, America and Africa. There are two cultivated types of citronella grass, which are Ceylon (Mahapengiri) and Java (Lenabatu) citronella. Java citronella known as Cymbopogon winterianus Jowitt while Ceylon citronella known as Cymbopogon nardus (L) Rendle [3]. Normally, the plant is planted in the kitchen gardens in Malaysia. Recently, the plants are planted commercially by entrepreneurs for essential oils extraction [4]. The citronella oil is comparatively high demand due to its