Data on dispersed phase holdup are presented for a range of aqueous-organic systems, and are used to assess the accurancy of existing methods for its prediction. The Griffith model (2) for the mixer-settler region and the Thornton correlation (3) for the dispersion region were found to be the most accurate for high interfaclal tension systems; however their application requires a knowledge of the transition pulse velocity. No technique was found to predict satisfactorily the measured holdup for the low interfaclal tension systems investigated. The refitted Bell and Babb correlation (14)was found to provide an accurate method of interpolating data for a particular system, and can also be used to predict the transition from mixer-settler to emulsion operation.