Polymers are widely used across multiple industries due to their distinct properties such as low density, tunable flexibility, ease of manufacture and cost effectiveness. The metallization of polymers by using chromium (Cr) and titanium oxide nitride (TiON) coatings gives the polymers’ surface distinct color tones, such as silver, gold, blue and red, allowing such parts to be used as a replacement of metal decorative parts in the automotive industry. Good quality metallized polymer surfaces, however, are challenging to obtain. Several properties of the metal layers must be guaranteed such as good adhesion, low pinhole and crack defect densities, high brightness and an intrinsic color. To overcome these challenges different deposition conditions and pretreatments (plasma etching) have been tested for the two systems, Cr and TiON, by magnetron sputtering. Parameters such as bias voltage, pressure and etching time were varied. For both systems, the plasma etching treatments in Ar atmosphere improved significantly the coatings’ quality. For the Cr, the maximum thickness achieved without forming buckling defects was 1400 nm. For the TiON system, thinner coatings were used and good results were achieved for different deposition configurations. Pure gold color needs low incorporation of contamination oxygen, making energetic particle deposition a desired feature. For blue and red color tones higher deposition pressures or increasing oxygen inlet fluxes can be used. Polymers such as polycarbonate (PC) and polyamide (PA) were successfully tested for both systems.