The mathematical model has been developed to investigate the physical absorption of CO2 using the hollow fiber membrane contactor. The model takes into account the effect of membrane pore size distribution. The simulation is thoroughly performed for various membrane properties and operating conditions. The pressure drop of the liquid flow in the lumen side of the fiber leading to the different wetting ratio (chi*) along the fiber length is presented. The wetting behaviors and degree of membrane wetting of the membrane with different characteristics such as pore size, pore size distribution, hydrophobicity, porosity, thickness, fiber diameter, and fiber length are reported. The membranes with large pore radius, high standard deviation and high porosity show higher CO2 absorption flux in completely dry mode operation. However, these membranes are sensitive to the membrane wetting if the liquid feed pressure (P-L0) is increased, resulting in absorption flux deterioration. In addition, the effect of important operating parameters including gas/liquid flow rates, gas composition and liquid temperature on absorption performance are also investigated. (C) 2011 Elsevier B.V. All rights reserved.