In this paper, a comprehensive dynamic model for melt polycondensation reactions in tubular reactors is presented. The model allows for axial dispersion and is capable of stimulating removal of low molecular weight by-products from the reaction mixture into an adjacent vapor phase. General features of the model include a generic kinetic framework that permits modeling of numerous polymeric systems and the ability to readily configure multistage systems. Simulation results are shown for two sample systems, the polymerization of polyamide 6 and polyamide 6,6. The model is suitable for analyzing startup and grade transition operations as well as for steady-state design. The model is also a useful tool for control system design.