The structure of alkaline earth vanadate glasses, xMO · (100-x)V2O5 (M = Ca, Sr, Ba, x = 30, 40, 45, 50, 55), has been investigated by means of 51V static and magic angle spinning (MAS) NMR spectroscopies. The 51V NMR spectral parameters of various constituent vanadate groups contained in the vanadate glasses were determined by the spectrum simulation with reference to those of various crystalline vanadates obtained previously. It was found that the structure of alkaline earth vanadate glasses consists mainly of VO4-tetrahedra in accordance with authors' previous results based on the IR study. It was deduced that for x = 50 the glass network is mainly constituted of one dimensional (VO3)n-single chains, and for x &le 45 the decrease of the MO content yields a mixture of the V2O5-rich phase constituted of three dimensionally branched VO4-groups and the MO-rich phase constituted of the VO5-trigonal bipyramids, followed by the decrease of (VO3)n-single chains.