The objective of this research study was to determine the effect of enzymatic and hydrothermal treating of seeds and of adding of antioxidant and vitamin E on the stability of cold pressed flax oil during storage. The initial research material consisted of flaxseeds of high linolenic variety “Bukoz”. Seeds were subject to the enzymatic and hydrothermal treatment at a temperature of 50°C during a period of 3 hours. A mixture was used of cellulase and protease enzymes in the form of Celluclast 1.5 L and Alcalase 2.4 L preparations. The oil was cold pressed in a “Farmet” screw press, and purified by the natural sedimentation and decantation. A mixture was used of the α-tocopherol, ascorbyl palmitate, and soy lecithine as the antioxidant, and the dl-α-tocopheryl acetate as the vitamin E. The oils were stored in brown glass bottles for 6 months, at a temperature of 6°C under the cooling conditions. The oils from the seeds without treatment were analyzed as were the oils from the seeds after treatment and those from the seeds after treatment with the antioxidant and vitamin E added. In the oils, the degree of hydrolysis was assayed as was the degree of primary and secondary lipid peroxidation; the oils were also sensory assessed. It was proved that the enzymatic and hydrothermal treatment of seeds before cold pressing exerted a beneficial effect on the oil stability during 6 months of storing them under the cool conditions. At the end of the storage period, the overall degree of the oxidation determined as a Totox index didn’t exceed 10 units, which define a good quality of edible oils. It was found that the enzymatic and hydrothermal treatment of seeds caused significant changes in the sensory characteristics of oils, in which a strong “crust of bread” note appeared. During storage, the intensity of that note decreased and the intensity of the “oxidized” and “bitter” note increased; the final assessment of overall palatability of oil was at the limit of acceptability and totalled 6 points on a 10 point scale. The antioxidant added in the amount of 150 mg/kg delayed the primary and secondary oxidation processes and, also, reduced unfavourable sensory changes. The dl-α-tocopheryl acetate added in the amount of 400 mg/kg made it possible to reach a recommended Harris coefficient (0.6).