The aim of this work was to evaluate the effect of phenolic extract addition on the oxidative stability and antioxidant activity of mayonnaise. The mayonnaise was enriched with different concentrations (50, 150 and 300 mg kg-1) of Olive Leaf phenolic commercial extract and stored at 30°C for 30 days. Its quality was monitored for microbiological and sensory parameters, individual phenolic content, oxidative stability, antioxidant parameters. The analysis quantitative showed that all added phenolic compounds were transferred to the oil fraction., particularly a high concentration of hydroxytyrosol acetyl derivative (Hy-Ac) was detected (0.88 g 100 g-1). The addition of 150 mg kg-1 of extract allowed to obtain a mayonnaise more stable to oxidation, as demonstrated by a constant induction period over time. Hydroxytyrosol and hydroxyl acetyl derivate functionalized and improved the antioxidant activity of the analyzed samples as confirmed by their correlation with DPPH assay. Enriched mayonnaises showed good pH values and no microbial contamination was revealed. Furthermore, for the production of enriched mayonnaise is better to use lower concentration of phenolic extract (50 mg kg-1). An excessive use of extract can change the taste of the final product, making it unacceptable for the consumer.