Investigation of absorption of SO2 into aqueous slurries of fine and reactive hydroxide particle of calcium and magnesium was carried out in a stirred vessel at 298 K at realistically high mass transfer coefficients. Enhancement in the rate of gas absorption was measured at different solid loadings and speed of agitation. The absorption process is theoretically analyzed using two different models. For the SO2-Ca(OH)(2) system, a single reaction plane model was used and for the SO2-Mg(OH)(2) system, a two reaction plane model incorporating the solids dissolution promoted by the reactions with the absorbed SO2 in the liquid film was employed. A correct procedure was adopted to estimate the contribution of the suspended particles in the enhancement of gas absorption. Theoretical enhancement factors thus obtained compared well with the experimental data. The extra enhancement observed for the SO2-Mg(OH)(2) system could be explained from the reaction between SO2 and the dissolved [SO3](2-).