Composition of higher fatty acids, peroxide value (PV), acidic value (AV), as well as colour of raw, commercial rape oil and oil fraction formed after each of seven heating cycles of the oil conducted in two ways – with and without frying potato chips, were compared. After each heating of the oil, the duration of which corresponded with time required to fry potato chips, it was cooled down to room temperature and stored in conditions simulating those of a small gastronomy restaurant. The goal of undertaken research was evaluation of physicochemical properties and usability of post-frying sunflower oil as a substrate for biofuel production. Utilization of post-frying sunflower oil as a fuel seems to be justifiable when the beneficial ratio of saturated and unsaturated fatty acids in oil fraction, a property that stabilizes as a result of surface contact with potato chips, as well as ecological (utilization of waste) and economic (partial substitution of crude oil derived fuels) benefits are taken into consideration.