Abstract: The specific features of hypersound propagation in aqueous solutions of nonelectrolytes in dependence on frequency and temperature have been investigated using Mandelstam-Brillouin spectroscopy. Nontrivial temperature behavior of hypersound at small Mandelstam-Brillouin scattering angles is observed in the vicinity of solution singularity. The temperature dependences of hypersonic velocity in aqueous solutions of methylpyridines at different frequencies have been analyzed.