Five vegetable oils were tested. We have analysed peroxide and iodine value of vegetable oils during the ozonation. The ozonation process was conducted in the 150 cm(3) laboratory bubbling batch reactor The oxygen-ozone mixture was delivered through the bubbler into the oils. We used the ozone concentration in the range of 10 - 300 mgO(3)/g of oil. The most commonly available oils in Poland were compared: sunflower oil and rapeseed oil. Ozonation reduced the iodine no., and increased the acid and peroxide no., and viscosity. The results showed lack of significant differences between properties of both oils. It was found that ozonized sunflower oil can be a good substitute for ozonized olive oil because of the similarity of peroxide number obtained after the ozonation.