For the first time, the dynamics of the accumulation of essential oil in the underground organs of Ferula foetida grown on the territory of the Mangistau region (the Western Kazakhstan), depending on the age of the plant and the place of growth, are investigated. The maximum accumulation of essential oil is noted for the 4th year of vegetation (0.98%), the minimum β for the annual plants (0.14%). The largest quantitative composition of essential oil is noted in the sands of Tuyesu and on the elevation of Tynymbay Shoky, the minimum β in the vicinity of the Karkol wintering. As the results of the study the optimal places of raw materials harvesting and collection dates are determined