The Mg 100Àx Pd x (x ¼ 10, 20 and 30), Mg 80 Ni 20Ày Pd y (y ¼ 5 and 10) and Mg 75 Ni 20 Pd 5 amorphous alloys were prepared by the singleroller melt-spinning technique. The electrical resistance was measured during electrochemical hydrogen charging in 6N KOH solution. The Mg 90 Pd 10 amorphous alloy shows larger increase in the electrical resistance by hydrogen absorption than any other alloys prepared in this study. Moreover, the electrical resistance of those alloys was also measured in hydrogen-dissolved water prepared by the bubbling method. As a result, it was found that the electrical resistance increases with increasing immersion time and that the increase amount of the electrical resistance is dependent on the alloy composition. The increase amount of the electrical resistance of the Mg 90 Pd 10 amorphous alloy is much larger than those of other alloys prepared in this work. The increase amount of the electrical resistance of the Mg 90 Pd 10 amorphous alloy after immersion in hydrogen-dissolved water for 300 s is dependent on the concentration of hydrogen in water, and it increases with increasing hydrogen concentration in water. From these results, it is confirmed that hydrogen absorption has a great influence on the electrical resistance of the Mgbased amorphous alloys and that the sensitivity to hydrogen can change largely depending on the alloy composition even in the similar alloy systems.