Abstract: Nonlinear acoustic methods are found increasing applications during the last decades. They are effective for diagnostics of bubbles in liquids and cracks in solids since bubbles and cracks are strongly nonlinear scatterers. In this paper the nonlinear acoustic techniques for imaging of liquids and solids with the nonlinear acoustic defects are described Results of investigation demonstrate possibilities of the nonlinear acoustic techniques in nondestructive testing of different media.