The simultaneous absorption of H2S and CO2has been studied both experimentally and theoretically. A model has been developed which predicts the absorption rates of H2S and CO2into a sodium carbonate solution. The absorption rates are calculated according to the two-film theory. In the liquid film, the finite rate of the CO2reaction was considered. Otherwise, in the liquid film as well as in the liquid bulk, equilibrium conditions for all reactions were assumed. Absorption experiments were performed on a packed column using a counter-flow strategy. In the experiments the influence of the initial carbonate concentration, the gas flow rate and the temperature on the removal efficiencies of H2S and CO2and the selectivity of H2S were investigated. It is desirable to absorb the H2S but not the CO2. The agreement between the absorption model and the experimental results from the absorber tower was satisfactory. The mass transfer coefficients were determined by fitting the experimental data to the model with respect to the H2S and CO2content in the outgoing gas. The H2S content was used to determine the gas side mass transfer coefficient and the CO2content was used to determine the liquid side mass transfer coefficient, The effective contact area of mass transfer was taken from published data. With a constant packing height, both the experiments and the model indicated that high carbonate concentration benefits the removal efficiency of H2S. Higher gas flow rate also benefits the selectivity for H2S. However, the removal efficiency will decrease. At higher temperatures the selectivity and the removal efficiency of H2S decreased. Under the conditions investigated, the absorption of H2S was essentially controlled by gas-side mass transfer and the absorption of CO2was controlled by liquid-side mass transfer