This investigation presents the use of the electrochemical ion detection to evaluate the permeability of TiN coatings deposited using physical vapor deposition (PVD). The ferrous iron ions Fe(II) produced due to the anodic dissolution of the substrate were used as indicators of the permeability of the coating. A Pt-mesh located on the sample surface was used as ion detector. It was polarized at the oxidation potential of Fe(II) into Fe(III). The measurements were carried out on ten different Ti-TiN coatings, deposited on steel DIN EN ISO X153CrMoV12. The samples had different degrees of permeability and they were used to evaluate the capabilities of the proposed test setup. The coatings were prepared with different interlayers and top layers thickness. Furthermore, two different structures of the TiN layer were deposited and evaluated. The measurements were done both with and without polarization of the samples. The electrochemical ion detection showed excellent capabilities to investigate the permeability of the coatings.