Liquid phase residence time distribution studies are reported in 2-phase inverse fluidized bed for the first time in the literature. Using a pulse tracer technique and deconvolution method of analysis, RTD of the system, residence time, Peclet number and dispersion coefficient are determined. The liquid phase axial dispersion coefficient increases with increase in liquid velocity and Archimedes number and is independent of static bed height. An empirical correlation has been proposed for liquid phase axial dispersion coefficient in 2-phase IFB. (C) 2003 Elsevier B.V. All rights reserved.