The comparison of anodic dissolution rates of two heat resistant tungsten (12 % weight) and tungsten and rhenium (8 % W – 6 % Re) alloys in chloride, nitrate and chloride-nitrate (30 g/l NaCl + 120 g/l NaNO3) electrolytes has been fulfilled. It is shown that excess of critical current density (icr) depending on hydrody-namic conditions leads to: falling dependence of current efficiency on current density and absence of influ-ence of solution content on dissolution rate. The mechanism of mass transfer, determining dissolution rate and structure of superficial layers at i > icr is discussed. Data on chemical content of surface layers depending on machining modes are presented. The modes of electrochemical machining (ECM) of parts made of these alloys for achievement of best performance parameters of ECM are offered.