Internal friction and ΔE-effect measurements have been made on Metglass 2826 and other ferromagnetic metallic glasses, electrolytically charged with hydrogen. Initially, the ΔE-effect and magnetoelastic damping are strongly suppressed. The internal friction is dominated by a peak attributed to the stress-induced reorientation of interstitial hydrogen atoms, with a mean activation energy of 0.5 eV. Various aging effects occur after charging. Recovery of charge-induced bending is followed by a slower decline of the reorientation peak, a recovery of the ΔE-effect, and an accompanying transient appearance of a magnetoelastic internal friction peak. The observed behavior indicates a strong interaction of hydrogen with domain walls, and leads to the prediction, confirmed experimentally, that hydrogen degrades the soft magnetic behavior of these alloys.