The origin of Zr 65 Al 7.5 Ni 10 Cu 12.5 Pd 5 and Zr 65 Al 7.5 Ni 10 Cu 12.5 Nb 5 glassy alloys exhibiting a remarkable plastic strain of about 6% and over 10%, respectively, under compressive deformation is compared. Observation by transmission electron microscopic (TEM) indicates that the deformation-induced structural transformation from monolithic glassy phase is responsible for the large plasticity. The degree of structural change, however, is different between both alloys: the fcc-Zr 2 Ni crystals emerged within glassy phase for the former, while only ordered clusters were observed for the latter. The difference is suggested to correlate to the slower grain-growth of the primary crystallization phase in the Zr 65 Al 7.5 Ni 10 Cu 12.5 Nb 5 compared to those in the Zr 65 Al 7.5 Ni 10 Cu 12.5 Pd 5 alloy.