Tilapia is one of the most produced fish in the world and the most produced in Brazil. Despite its popularity, it has low levels of Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), responsible for several benefits to human health. Including EPA and DHA can be an alternative for nutritional enrichment of tilapia sausages. However, strategies must be used to minimize oxidative processes. Therefore, our objective was to evaluate the antioxidant effect of oregano extract added to tilapia sausage enriched with EPA and DHA. We divided into two groups the sausages that were produced supplemented with EPA and DHA: with the addition of oregano and without the addition of oregano extract (0.5%). The phenolic compounds of the oregano extract and the antioxidant activity of the sausages were evaluated during 90 days of storage at -18 °C. The phenolic compounds of the oregano extract were 104.7 mg EAG/g, and its addition to sausages reduced lipid oxidation during storage. The oxidation of sausages with oregano extract over time (days) may be represented by the equation: Oxidation = 0.0576*time (R2 = 0.62). The oxidative processes of sausages without the addition of extract can be represented by: Oxidation = 0.0721*time (R2 = 0.75). Thus, we suggest the inclusion of oregano extract as an antioxidant agent in tilapia sausages with the addition of EPA and DHA.