The sensitivity of the N2O distribution in our two-dimensional photochemical model to horizontal diffusion coefficients (both Kyy and Kyz values) has been explored. The residual circulation was computed using temperature data from the National Meteorological Center (NMC) and heating rates from Rosenfield et al. (1987). The Kyy and Kyz values were computed from these same data using quasigeostrophic potential vorticity. For comparison we also computed self-consistent Kyy values from our residual circulation. The use of either set of these diffusion coefficients produced substantial changes in the N2O distribution, especially in the middle to upper stratosphere and at high latitudes in the winter. In general, the changes lead to an enhanced transport of N2O to higher latitudes with the set of self-consistent Kyy values transporting the greatest amount of N2O. The enhanced transport increases the lifetime of N2O because the photochemical lifetime is larger at high latitudes. ¿ American Geophysical Union 1988