Solid state NMR spectroscopy has been very useful in determining the structure of amorphous solids. Bioactive glasses have been studied by Si and P solid state MAS NMR spectroscopy. The chemical shift from MAS NMR is indicative of the type of chemical species present in the glass. The Si MAS NMR spectroscopy showed that Bioglass 45S5 was a Q2 type-structure with a small amount of Q3; i.e., silicate chains with a few crosslinks. The P MAS NMR revealed predominately Q0 species; i.e., PO; subsequent MAS NMR spectroscopy measurements have shown that Si-O-P bonds are below detectable levels