Wood polymer composite is an important material class for industries. Microbiological properties can be an important aspect to enlarge its application base. The biocidal properties of wood polymer composite (WPC) can be aggregated by incorporation of biocidal additives on its composition. But, an important aspect is the evaluation the influence of the fabrication process on its biocidal properties. In particular, the temperature and screw velocity are important parameters for extrusion processes, and the mass proportions of the compounds are important factors to define the WPC properties. Different combinations of process conditions and mass proportions of the composite can promote variation in the magnitude of the bactericidal effect. The bactericidal properties are aggregated in the composite by organic bactericidal additive and the high temperature and high shear rate during the extrusion process can affect the effectiveness of the bactericidal additive function. This paper investigates the effects of the extrusion process parameters associated with different percentages of bactericidal additives on the WPC. The results showed significant effects on the bactericidal properties that depended only on the bactericidal content.