For different applications, it is on interest to understand the relationship between the microstructure and the transverse permeability of a plasma sprayed coating. In the SOFC field, for example, the electrodes are very often characterized in term of porosity, particularly when they are elaborated by sintering. This can’t be applied to thermally sprayed coatings because of their very singular microstructure, lamellar and isotropic, depending strongly on the initial material and plasma conditions. In this study, coatings were manufactured by plasma spraying using different spraying parameters, many proportion of a porous agent, metallic or ceramic powders and two particles size in order to obtain various microporous structure. Measurements of their permeation with the pressure drop method and their open porosity just as the observation of the morphology and the structure by optical microscopy were achieved. The different data show that the evolution of the transverse permeability with the open porosity follows the Kozeny-Carman equation. This result correlated with the microstructural observation highlights the relationship between the permeability and the physical properties of porous plasma sprayed layers.