A rotating-bucket contactor is an interesting equipment used in liquid-liquid extraction. Of course, as in other contactors, axial dispersion widely affects the extraction efficiency. A theoretical approach to the problem is presented here. The paper reports also experimental data obtained in a contactor of conventional geometry. The data are analyzed and compared with model previsions. The agreement with the experiments is satisfactory. The obtained correlations adequately describe also some literature experimental data related to smaller equipment. Analysis and identification of the main fluid-dynamic aspects affecting axial dispersion can suggest modifications of the internal geometry of the buckets and compartments. In this way, the detrimental effects of the dispersion can be reduced, and the contactor efficiency can be improved.