The diffusion coefficients for nitrous oxide in aqueous solutions of diethanolamine (DEA) and N-methyldiethanolamine (MDEA) were determined using a wetted-sphere absorber over the temperature range 293-368 K. The ranges of amine concentrations covered in the experiments were 10-30 mass % for DEA and 10-50 mass % for MDEA. The diffusion coefficients indicated a linear dependence on amine concentration, but the temperature dependence was nonlinear. It was found that the diffusivity of N2O in aqueous DEA is always less than that in aqueous MDEA under equivalent conditions of amine concentration and temperature.