Diffusion coefficients of the potassium salt of taurine, sarcosine, L-proline, and glycine have been determined in aqueous solutions using the Taylor dispersion technique over a temperature range from (293 to 368) K and salt concentrations ranging from (0 to 3.0) mol . dm(-3). The diffusion coefficients of absorbed N2O in aqueous solutions of the potassium salt of taurine, sarcosine, L-proline, and glycine have been determined 3 over a temperature range from (293 to 333) K and salt concentrations ranging from (1.0 to 3.0) mol . dm(-3) The experimental results have been compared to estimated values from a modified Stokes-Einstein relation and available literature data. The diffusivities can be estimated with sufficient accuracy using a modified Stokes-Einstein relation. The diffusion coefficients of CO2 in the aqueous amino acid salt solutions can be estimated by means of the N2O analogy.