ABSTRACT: The recent approach in food technology focus on finding not only safe and natural biocide, but also being an alternative for the chemical preservatives. marinades have the ability to act as bactericidal, antitoxigenic, virucidal, fungicidal, antiparasiticbesides being flavouring agents. So, it considers a promising new concern to fulfill this purpose. The present study designed to evaluate the effectof some marinades on safety and shelf life of tilapia fish fillets stored by chilling at (4 ± 1ºC) by using  a-Fresh lemon juice (100 ml). b-thyme (4 g/kg). c-pomegranate peel extract(PPE)(1%v/w). and to screen the bioactivity of the aforementioned marinades .The  mean count of the APC in the untreated groups was 5.96±0.02, 6.85±0.02 and 7.63±0.02 log₁₀ cfu/g at zero day,3^rd and 6^th day, respectively. WhileThe  mean count of the APC in thegroups treated withFresh lemon juice (100 ml) was  5.01 ± 0.02, 5.38 ± 0.02, 6.04 ± 0.02, 6.51 ± 0.02, 7.05±0.02 and 7.59 ± 0.02 log₁₀ cfu/g at zero day, and 3rd, 6th, 9^th, 12 ^th and ^15th day, respectively, While the mean count of APC of thyme (4 g/kg) was 5.06 ± 0.02, 6.01 ± 0.02,6.26 ± 0.02, 6.86 ± 0.02,7.62 ± 0.02log₁₀ cfu/g at zero day, 3rd, 6th, 9^th,12th and 15^th day,respectively.The mean count of APC in groups treated with pomegranate peel extract(PPE)(1%v/w) was 5.15±0.02, 6.13±0.02, 6.95±0.02 and 7.59±0.02, respectively.In this study the antibacterial effect of Fresh lemon juice (100 ml), thyme (4 g/kg) and pomegranate peel extract(PPE)(1%v/w)was recorded and proved with varying degree of potency leading to extent the shelf life of the tilapia fish fillets. So, it could be utilized effectively as bioactive agents.