Ultrasonic Resonator Technology (URT) is a novel technology that has demonstrated potential to become an analytical method of choice for the physical characterization of solution and dispersions in pharmaceutical R&D and manufacturing. In contrast to many analytical techniques that rely upon characterisation of the solute’s electromagnetic properties, URT allows for direct probing of the mechanical properties of solutes including the surrounding media. Ultrasound is an oscillating mechanical wave, which compresses and dilates the distances between molecules. As a consequence, URT quantifies intermolecular forces (in the case of large molecules also intermolecular forces) and their change over time or temperature. The higher the change in forces (i.e. high solute concentration, strong interactions forces), the higher the sensitivity of the ultrasound velocity is. More important, URT will reflect the sum of the forces present in the sample of interest and is therefore particularly suited for bulk analysis. URT has thus become an innovative tool to characterize solute concentration, aggregation, degradation, and other structural changes in liquid samples. In particular, when investigating the stability of (nano-) emulsion, or (nano-) dispersions URT provides complementary information with the benefit of being either more sensitive, more rapid, or allowing for undiluted analysis. URT´s enormous sensitivity is currently applied to solve analytical problems in the pharmaceutical, chemical, food processing and cosmetics industry.