This paper describes the definition and concept of dispersibility and dispersion stability and explains that it is important to clarify the differences between these definition/concept to use. Ultrasonic attenuation spectroscopy and sedimentation analysis method are introduced as characterization methods applicable to highly concentrated dispersions in order to evaluate the extent of aggregation/dispersion state without dilution. As choice of the method properly depends on what and why will be measured, characteristics of each methods and examples of the measurement for practical dispersions were shown.