The effect of the gas and liquid flow rates on the mass transfer rate in laminar gas streams in wetted-wall columns with cocurrent gas-liquid flow was studied. An analytical solution was obtained for the average gas-phase Sherwood number as a function of the gas-phase Graetz number and the dimensionless interfacial gas velocity. Experiments were carried out on the absorption of ammonia into sulfuric acid solution and of methanol vapor into water, using three columns of different dimensions. The agreement between the experimental and the predicted effects of both gas and liquid flow rates on the gas-phase mass transfer rate was found to be fairly good.