Theoretical assumptions suggest that chitosan might be, owing to its good antioxidant properties, a component of a set of additives, which are able to eliminate a nitrate(III ) compound from the production of sausages. The antioxidant activity of chitosan depends on the method of how it is obtained, on its molecular structure, and on the properties of biological material, to which it was added. The objective of the research study was to determine the antioxidant effectiveness of chitosan with different molecular weight values that was added, together with lycopene, to medium comminuted pork sausages stored under the refrigeration conditions for 35 days. The antioxidant properties of chitosan were determined based on: the AV values, MDA concentration and content of fatty acids, and colour parameters. It was shown that the chitosan of a molecular weight of 135·10³ Da, was characterized by the strongest antioxidant activity. Together with the lycopene, it acted as an agent protecting against oxidative changes, and its protective range was similar to that of the traditional curing mix. On the other hand, the chitosan of a molecular weight of 68·10³ Da had the weakest antioxidant properties. The decrease in the content of PUFAs in the sausages with the added chitosan of a molecular weight of 68·10³ Da was about twice as high (2.1 mg/g fat) compared to the sausages with the added chitosan of a molecular weight of 135·10³ Da (1.1 mg/g of fat). In the sausages analyzed, the ratio between the n-6 series and n-3 series fatty acids in the sausages tested was three times higher than the desired ratio (12.9 – 16.3 ), and it was typical for the pork meat.