Penicillin G is a natural antibiotic with secondary metabolites properties. Since the penicillin is the most widely used antibiotic in the world, efforts in the pharmaceutical industries is focused on using the ingredients which are inexpensive and easy to access but have higher yeild of production. In this study Penicillin G was produced by Penicillium chrysogenom PTCC No. 5033. The total process was formed of three stages of sporulation, preparation of inoculum -pre-fermentation- and fermentation. To determine the optimal amount of carbon, nitrogen and phenyl acetic acid we used experimental design method, Taguchi, by using Qualitek software. The carbon source was wheat starch and rice bran was our nitrogen source.