This study presents a numerical simulation using computational fluid dynamics (CFD) of momentum and mass transfer in a hollow fiber membrane contactor for laminar flow conditions. Axial and radial diffusion inside the fiber, through the membrane, and within the shell side of the membrane contactor were considered in the mass transfer equations. The simulation results were compared with the experimental data obtained from literature for CO 2 absorption in pure water. The simulation results indicated that the removal of CO 2 increased with increasing liquid flow rate in the shell side. On the other hand, increasing temperature and gas flow rate in the tube side have an opposite effect.