Green or black tea decoction is a popular beverage in Tunisia, Libya and Algeria. It is prepared by cooking the dried tea leaves for a relatively long period of time, which is different from the infusion. The aim of our study was to evaluate the phenolic compounds content and the antioxidant and antibacterial activities of tea extracts after different cooking times, in comparison to tea infusion. Green or black tea leaves (40 g per L of water) were cooked for three times (15, 30 and 60 min) with two different methods (continuously and discontinuously). Tea decoctions obtained were extracted by acetone/water (v/v) according to the method described by Dhaouadi et al. (2011). Phenolic compounds were quantified by Folin -Ciocalteu method and their identifications were obtained by RP-HPLC/LC-MS technique. The antioxidant activities were evaluated by ABTS, DPPH and FRAP methods using Trolox as standard. The analysis of antibacterial activities of the tea preparations were assessed by using collection of microorganisms strains, commercially available as references. Values are means ± S.E.M., compared by ANOVA. Our results showed that the green tea cooked for 15 min contained the higher quantity of phenolic compounds (1388 ± 52 mg / gallic acid equivalent (GAE)/100mL of tea decoction). For the black tea, the higher phenolic compounds content were obtained 30 min after continuously cooking (953 ± 40mg /GAE /100 ml of tea decoction). Detailing of phenolic compounds peaks from different tea decoction extracts was described in the poster. The stronger antioxidant properties corresponded to those obtained from green tea cooked for 15 min (4975 mmol/ equivalent Trolox /100 mL of decoction). The antibacterial potential of tea extract showed that staphylococcus aureus and staphylococcus epidermidis were the most sensitive studied strains. Phenolic compounds of tea extracts from green tea cooked for 15 min are more powerful on the antioxidant and antibacterial activities, followed by black tea decoction obtained 30 min after continuously cooking, than tea infusion or decoctions of other cooking times.