Since diamond like carbon layers feature excellent mechanical and tribological behavior under defined environmental circumstances, they are well established in a wide field of industrial and automotive applications in the last decade. However, the pretreatment of the substrate plays also an important role in supporting and enforcing the excellent properties of the coatings. This work analyses the effect of the plasma nitrided cold working steel substrate (80CrV2) on the adhesion, friction and wear resistance of DLC-coatings and compares it to the performance of DLC-coatings applied on a non-hardened substrate material. Therefore the grinded and polished specimens were nitrogen-hardened in an Arc-PVD (Physical Vapor Deposition)-device before the DLC-coating was applied in a Magnetron Sputter-PVD-process. In order to measure the hardness of the thin film coating, a nanoindenter was used. The adhesion was tested with a scratch tester and the wear resistance was measured by using a Ball-on-disc-tester. A 3D-profilometer and a SEM (Scanning Electron Microscope) were utilized to analyze the scratches and wear tracks on the samples. With these results correlations between the substrate nitriding and the mechanical and tribological performance of the DLC-coating were made.