In this contribution, we present the analytical solution of the one-dimensional dispersion model in the form of a partial differential equation for a continuous flow mixer with Danckwerts' boundary conditions. The suggested solution enables the description of change of concentration of species in the system as dependence of time and spatial coordinates. The results are explicit relations for different initial spatial distributions of species concentration in the flow mixer as well as for changes in species concentration in the inlet flow as a function of time. (C) 2003 Elsevier Ltd. All rights reserved.