The properties of plasma spray coatings are directly related to the type and characteristics of the powder, deposition parameters, type of material and the morphology of the substrate. Key properties of the coating are toughness, strength, shear, hardness, inter surface toughness and adhesion of the coating. Adhesive strength determines the quality of the coating, while the cohesive strength of layers determines the lifetime of the coating in service. These properties are very important for biomedical inert and reactive ceramics which are deposited on implants. Plasma spray coatings show inter surface complexity with the substrate due to the influence of residual stress, porosity and micro cracks at the inter surface. Therefore, for each coating, adhesion strength must be examined. There are several methods of measuring joint adhesion strength of thermal spray coatings of which most commonly used is the method of tensile testing. Presented in this paper is the Vickers method of inter surface diamond pyramid indentation testing at the interface substrate/coating, which is used to determine coating adhesion strength.