•Platinum and nine noble metal dental alloys were investigated according to ISO 10271.•The different electrochemical parameters in 0.9 % NaCl were determined and discussed.•Based on the electrochemical behavior, alloys were classified according to the noble metal (Au, Pt and Pd) content.•The classification was proposed using classification of of the American Dental Association. Platinum and nine commercial dental alloys with the contents of noble metals ranging from 27 wt.% to 97.6 wt.% were investigated by the procedure described in the Standard ISO 10271:2009, Electrochemical testing was performed in an argon purged solution of 0.9 % NaCl at pH = 7.2. The obtained values of the characteristic determined parameters of the alloys with different noble metal content, treating only Au, Pt, and Pd as noble, were compared with the American Dental Association (ADA) classification system. Based on the obtained results, the considered noble metal dental alloys were classified into three groups.