In order to investigate the atomic and electronic structures of the melt‐spun metallic glass system La100−xAlx(18≤x≤45), measurements of the27Al NMR Knight shift and linewidth, as well as the magnetic susceptibility, have been carried out. The dependence of these quantities on the Al concentration shows a change in behavior atx=25, which corresponds to the equilibrium crystalline phase, La3Al, and is discussed in terms of a model previously introduced for the atomic structure. An analysis of the magnetic susceptibility indicates that thed‐electron spin/orbital contributions dominate due to a larged‐electron density of states at the Fermi energy. Values of 82 and 23 kOe per &mgr;Bofsanddspin, respectively, were obtained for the hyperfine coupling.