Body armors consist of fabrics made of high performance fibers which are characterized by low density, high strength, high tenacity and high energy absorption. Soft body armors are produced with lamination of 20-50 layers of fabrics and hard body armors consist of ceramic/metal plates along with the fabric. However, these armors are bulky, heavy, non-flexible. In order to eliminate disadvantages of traditional armors, new armor concept has been come into use with impregnation of shear thickening fluids (STFs) onto soft body armors called as liquid body armors. STFs are used within the fabrics to improve the ballistic and stab resistances due to its flowable behavior under ordinary conditions and become a rigid solid when a strong impact is applied. Objective of this study is to develop flexible, lightweight and high protection level soft body armors with the impregnation of shear thickening fluids onto fabrics. In this study, for the production of STFs, colloidal and fumed silica nanoparticles were employed. As the carrier fluid polyethylene glycols (PEG) with three different molecular weights were used. The STFs were prepared by sonication of nanoparticles within the carrier fluid. The rheological behaviours of STFs were investigated using a rheometer. Two types of composites were fabricated by impregnating of STFs onto aramid and UHMWPE mat fabrics. The stab resistances (quasi-static and dynamic), flexibility and ballistic features of composites were tested and compared with neat fabrics. The microstructural surface coating features of STF and composites were also characterized by using scanning electron microscope (SEM).