A Unidirectional, two-fluid model based on the volume-average mass and momentum balance equations was developed for the prediction of two-phase pressure drop and external liquid hold-up in horizontally positioned packed beds experiencing stratified, annular and dispersed bubble flow regimes' The so-called slit model drag force closures were used for the stratified and annular flow regimes. In the case of dispersed bubble flow regime, the liquid-solid interaction force was formulated on the basis of the Kozeny-Carman equation by taking into account-the presence of bubbles in reducing the available volume for the flowing liquid. The gas-liquid interaction force was evaluated by using the respective solutions of drag coefficient for an isolated bubble in viscous and turbulent flows. The proposed drag force expressions for the different flow patterns occurring in, the bed associated with the two-fluid model resulted in a predictive method requiring no adjustable parameter to describe the hydrodynamics for horizontal two-phase flow in packed beds.