The use of antibacterial filter media is a method employed for the removal or inactivation of athogenic microorganisms in filteration of liquids. In this work fibers with antibacterial properties for production of filter media were manufactured, using a melt spinning system. Polypropylene granules were blended with nanosilver masterbath having a ppm strength of 200,000. The fibers were used to make fourteen nonwoven needled filter medias, using carding and needling machines. The effect of parameters such as fibers fineness, nanosilver content in the polymer and punch-density on antibacterial properties of the filters have been investigated. Additionally the effect of other parameters such as existence of silica in masterbatch and fibers, distribution of nanoparticle in the polymer, thickne and weight per unit area of the samples, together with their air permibility were also investigated. Antimicrobial tests were carried out using stable and flow methods on the exprimental samples. The results showed that not only nanoparticles distribution in the polymer is relatively uniform along the axis of the fibers, but also the existence of silica in the fibers increases filter eficiency. It was also found that a linear regression exists between antibacterial properties and fineness of the fibers and the amount of added nanosilver, it must be pointed out that fineness is the most influential factor. As far as the effect of punch density is concerned, it was found that unlike the above factors a nonlinear regression exists between punch-density. The influence of punch-density on antibacterial properties of filter is considerably a lot less than that of fibers fineness or the add-on percent of the masterbatch. Considering the above results, it can be said that, the manufactured filters can be employed in a wide range of liquid filteratio processes.