An analytical solution of the soil-gas diffusion equation coupled with the convective-dispersive solute transport equation under transient conditions is presented. A first-order transformation scheme, a linear, equilibrium, solute adsorption isotherm, gas transport by diffusion, and equilibrium gas solubility were assumed. The solution was obtained by means of Laplace transforms for zero initial concentrations and semi-infinite conditions for both species. Depth and time distribution profiles for soil gas were computed for the intervals 0 <t<,t1, andt>t1, wheret1= time of solute application. Measured values of N2O produced and transported simultaneously with a pulse of NO3- fertilizer in a 1.0-m long soil column were used to demonstrate the applicability of the solution. By using a fitted soil-gas diffusivity and a denitrification rate constant, reasonable agreement was found between predicted and experimental concentration profiles of N2O, especially for early times.