Polyamide 6 is usually modified with ethylene-propylene-diene-rubber to improve the impact strength whilst reducing the Young’s modulus and limiting the processability. As an alternative a specific impact modifier for PA6 was developed at the Institut für Kunststofftechnik that is made of PA6/polyether-block copolymers and compounded it into PA6. The block copolymers were made by reactive extrusion and consist of relative stiff PA6-segments and relative soft polyethertriol-segments. The PA6-segments co-crystallize with the PA6-matrix and create a good bonding. With this novel impact modifier the impact strength of PA6 is improved without reducing the stiffness strongly. The mechanical and morphological properties of PA6-blends with a differential amount of PA6/polyether-block copolymers are compared with the properties of a commercially available ethylene-propylene-rubber. The morphologies of all polymer blends were analyzed by transmission electron microscopy, scanning electron microscopy and atomic force microscopy. Tensile tests and Charpy impact tests were performed to investigate the mechanical properties. The results show that the impact strength of PA6 with a little reduction of the stiffness and the processability can be improved.