This paper presents a new vegetable oil that is jatropha curcas seeds oil as a substitute for mineral oil. This product has several advantages among which the fact that it is non-food crops and may be grown on low fertile soils and areas where annual rainfall levels are significantly lower than those required by other plants used to extract other vegetable oils such as rape-seeds, sunflower, corn, soybeans, grape-seeds and sesame. The considered natural ester oil is processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce jatropha curcas methyl ester oil (JMEO). The physicochemical (water content, relative density, viscosity, acidity, visual examination, color, iodine number, corrosivity, flash point, pour point) and electrical (breakdown voltage under ac, dc and impulse voltages) properties of JMEO are presented and discussed. A gas chromatography (GC) analysis is also achieved to identify the methyl ester components in JMEO. The breakdown voltage of JMEO is compared to that of mineral oil (MO). It is found that the average breakdown voltage of JMEO and MO under different voltage waveforms are too close.