We have investigated the hydrogen permeation of the melt-spun Zr65Al7.5Ni10Cu12.5Pd5 alloy in the supercooled liquid, the quasi-crystalline particle-dispersed glassy and the crystalline states. The hydrogen permeability of this alloy is highest in the supercooled liquid state and is lowest in the crystalline state, compared among the three different structures. The hydrogen permeability of the melt-spun alloys consisting of quasi-crystalline particles-dispersed in the glassy state is intermediate between the single phase glassy, and the crystalline alloys. This is presumably because the Zr content in the residual glassy phase decreases after the primary precipitation of the icosahedral-phase (i-phase), resulting in a decrease in the hydrogen permeability. (c) 2007 Elsevier B.V. All rights reserved.