Pultrusion is a famous continuous process to produce endless fiber-reinforced plastic profiles. Although thermoplastic matrices provide many different advantages compared to thermosetting materials, thermoplastic pultrusion has still not experienced a worldwide breakthrough on an industrial scale. As a result of their high melt viscosity, thermoplastic matrices cause problems during the continuous impregnation of the reinforcement fibers. The research investigates a pultrusion die for the production of axially reinforced endless tapes consisting of thermoplastic matrices. Focusing on the analysis of the impregnation process, computational and experimental investigations were carried out. By means of a known mathematical model from Koubaa et al., the penetration process of thermoplastic melts in porous fiber bundles was investigated and the influence of important parameters including pull-off speed, melt viscosity, fiber permeability, die length and die pressure on the impregnation process was analyzed within the scope of numerical calculations. Experimental studies of the pultrusion die were carried out on a purpose-built pultrusion line. In order to affect the residence time of the reinforcement fibers in the die, the length of the pultrusion die was adjusted by means of a modular die design. To analyze the influence of melt viscosity on the impregnation process, different thermoplastic materials including polypropylene and polyamide were investigated. To detect the influence of melt viscosity and residence time on the impregnation behavior, the cross-sections of the produced tapes were analyzed by means of an optical microscope. Based on the results of the impregnation process modeling and of the experimental data, the current pultrusion die was optimized, aiming for an improved impregnation behavior.