A theoretical and experimental study of the equilibrium interface configuration in stratified bicomponent tube flow of polymer melts is presented. In the theoretical analysis, the principle of minimum viscous dissipation is used to determine the energetically preferred interface configuration for the case of stratified flow of Newtonian fluids of differing viscosity. In the experimental analysis, it is demonstrated that both a nylon‐nylon and a xylene‐sugar water solution system attain the minimum viscous dissipation interface configuration under equilibrium conditions.