The mechanical properties and deformation mechanism of Sc 75 Fe 25 nanoglass and Sc 75 Fe 25 metallic glass pillars with diameter from 2 micrometers to 95 nanometers were investigated by means of ex-situ and in-situ compression tests. The results showed that the yield strength and deformation mechanism in the metallic glass were size-dependent while these in the nanoglass were not. It is suggested that the reduced shear band nucleation sites in metallic glass with decreasing sample size results in the increased yield strength and transition of deformation mode. In contrast, the glass/glass interfaces in nanoglass which have reduced density could serve as shear band nucleation sites and therefore promote multiple shear banding.