The usefulness of a rotating packed bed (RPB) in the absorption and stripping of ammonia and volatile organic compounds (VOCs) has been examined, and numerous correlations of the overall mass transfer coefficient (K(G)a) have been proposed in the literature. However, these correlations do not provide acceptable predictions concerning other experimental systems. In this study, a local gas-side mass transfer coefficient (k(G)a) in an RPB is calculated and an empirical correlation is proposed, based on 430 experimental K(G)a data gathered from the literature. Results showed that, with the aid of the two-film theory and the correlation of the local liquid-side mass transfer coefficient (k(L)a) reported in our previous work (Chen, Lin et al. 2006), most of the experimental K(G)a data could be reasonably predicted. The effects of gas flow rate, liquid flow rate, liquid viscosity, and centrifugal acceleration on K(G)a were found to depend on the ratio of the mass transfer resistances in the gas phase and the liquid phase.