Amorphous (FexMo1−x)75P16B6Al3with x=0.7, 0.8, 0.9, 0.95 and 1.0 have been studied by57Fe Mo¨ssbauer spectroscopy. The magnetic ordering temperature decreases drastically from 640 K for x = 1.0 to 26 K for x = 0.7. The result suggests an antiferromagnetic exchange interaction between Fe and Mo. Anomalous magnetic hyperfine interactions have been observed at 4.2 K. The P(H) analyses indicate a two‐maxima function of H. The intensity of the low‐field component increases with Mo content and at the expense of the high‐field component. This indicates that there is a substantial number of Fe atoms which are weakly magnetic or have small moments.