The mechanical relaxation in binary, ternary, quaternary, and quitary bulk metallic glasses with widely different glass-forming ability, or the critical cooling rate, has been studied. A single-roller melt-spinning apparatus was used for preparing thin specimens. The internal friction Q - 1 and the oscillation frequency f of the specimens were measured using an inverted torsion pendulum with the free decay method. The measurements were performed from room temperature, through the glass transition temperature T g , up to the crystallization temperature T x . As the temperature is increased, the background Q - 1 increases, and peaks can usually be seen near T g and T x . The shear modulus, which is proportional to f 2 , is changed near the Q - 1 peak. The experimental data are presented and overall features of the results are discussed.