The rates of polymerization of unhydrogenated and hydrogenated sunflowerseed oils were measured under atmospheric conditions in the various containers (glass, PET and metal). Polymerization rates showed a strong dependence on the degree of unsaturation and the light transmittance of the containers. The average molecular weights of polymerized oils were determined by viscosity measurements.The relationship between viscosity and average molecular weight was determined. It is seen that unhydrogenated sunflowerseed oil has a higher polymerization rate than hydrogenated oil samples in a glass container and they has higher viscosity values.