The electrochemical corrosion behaviour of as-prepared and structurally relaxed Zr48Cu36Ag8Al8 glassy alloy samples was investigated in 1M H2SO4. Results show that the active–passive transition behaviour of Zr48Cu36Ag8Al8 glassy alloy depends on the amount of free volume (FV) present in the metallic glassy alloy. Poor passivation due to active dissolution of Cu was displayed by the Zr48Cu36Ag8Al8 glassy alloy when it was in a high energy metastable state with relative high amount of FV. It is shown that by reducing the amount of FV in the glass, the passivation behaviour is significantly improved.