The aim of this study is to investigate and compare the corrosion resistance of real, ready-to-use dental crowns, fabricated of Co–Cr alloys by CAD/CAM milling and conventional melting-casting technology, in a solution of artificial saliva with different pH levels. All electrochemical corrosion measurements are carried out with MTechPGP-550M potentiostat/galvanostat in two stages. The temperature is kept constant at 37°C. In the first stage, an open circuit potential are measured relative to a standard silver chloride reference electrode as a function of the immersion time in the electrolyte. In the second stage, a potentiodynamic cathode-anode polarization curves are recorded with a velocity of 2 mV/s in a three-electrode cell consisting of a working electrode (crown), a standard silver chloride reference electrode and an auxiliary platinum electrode. The values of corrosion potentials, corrosion current density, potentials and current density of oxide film destruction, as well as a passivation region are obtained from potentiodynamic curves. Morphological and chemical changes of the surface are analysed by scanning electron microscope TESCANVEGO 3 with BRUKER energy dispersive analyser at an accelerating voltage of 20 keV after performing corrosion testing. As found, the dental crowns fabricated by the new method of CAD/CAM milling have greater corrosion resistance compared to the ones obtained by melting-casting technology. Some changes in microstructure and surface morphology are observed and this fact influenced the corrosion behaviour for the dental crowns. The pH level of artificial saliva affects the electrochemical parameters of corrosion. In an acidic environment at pH = 5.4, the corrosion rate for both types of crowns is highest, i.e. the corrosion resistance of crowns is reduced. In an alkaline environment at pH = 8.2, the milled crowns have the largest area of passivation, which is especially important for materials used in orthopaedic dentistry.