The flow behaviour of gas and liquid in wetted-wall columns was studied theoretically and experimentally for the cases of cocurrent and countercurrent laminar flow of both fluids. Analytical solutions were obtained for the velocity profiles of gas and liquid and the frictional pressure drop for the gas stream. Frictional pressure drops for the gas stream were measured for the air-water system and the air-glycerol solution system. Experimental results were in good agreement with the theoretical predictions.