Carbon dioxide was absorbed into water-in-oil (w/o emulsion) composed of aqueous droplets as dispersed phase and benzene solutions of polybutene (PB) and polyisobutylen, (PIB) as continuous phase in an agitated vessel to get the liquid-side volumetric mass transfer coefficient (k(L)a). The effect of viscosity, pseudoplasticity, viscoelasticity, and interfacial tension of the emulsion, and speed and size of impeller on the gas-liquid mass transfer were investigated. The elastic properties, considered in the form of the Deborah number, were found to decrease the volumetric mass-transfer coefficient. On the basis of experimental data of k(L)a, a dimensionless empirical equation for k(L)a was proposed using the Deborah number and interfacial tension as follows:k(L)ad(2)/D-eff = 6.348 x 10(-9) (d(2)Nrho/eta)(2.536)(eta/eta(o))(2.397)x (1 + 2461.3De)(-0.274) (sigma/sigma(o))(-0.039).