A 500 liter (130 gallon) stainless steel steam distillation unit has been built to extract volatile essential oils from aromatic plants. A 1.5 m × 0.75 m dia. steam vessel (hydrostatically tested @ 125 psi) serves as the distillation tank. Low pressure or high pressure steam is supplied by a diesel fuel fired boiler of 10 horsepower. The steam vessel can hold peppermint from plots of 25 m2 and extract approximately 100 ml of essential oil per distillation. The size of the tub was designed to provide oil in sufficient quantity for industrial evacuation or for pesticide residue analysis. Following the distillation, the vessel can be disconnected from the cold-water condenser and rotated on swivels to a horizontal position, permitting easy removal and re-filling of plant material. The entire extraction unit (vessel, condenser, boiler and oil collector) is suitable for mounting upon a trader, making it transportable to commercial farms or research stations. The extraction of peppermint and spearmint oils using this new system will be presented.