Acoustic waves and elastic vibrations are extensively applied in various engineering equipments and devices for technical diagnostics and non-destructive testing of various products and materials. The nonlocal elasticity theory is applied to study the propagation of plane wave and Rayleigh-type surface wave in transversely isotropic diffusive materials. The equations governing the motions in the medium are restricted for a plane. The time-harmonic solutions of two-dimensional motion equations are obtained and a velocity equation for homogeneous plane wave is derived. The two-dimensional equations are also solved to deduce a Rayleigh characteristic equation. The effects of nonlocality and material parameters on the speeds of plane and Rayleigh waves are illustrated graphically.