AbstractWe consider a linear system of Boltzmann transport equations. The system models charged particle transport in tissue, for example. Although only one species of particles, say photons, is invasing these particles mobilize electrons and positrons. Hence in realistic modelling of particle transport one needs a coupled system of three Boltzmann transport equations. The solution of this system must satisfy the inflow boundary condition. We show existence and uniqueness result of the solution applying coercitivity of the underlying linear operator and its adjoint operator. In addition, we consider existence of continuous solutions by iterative methods. Copyright © 2008 John Wiley & Sons, Ltd.