Blends of Nylon-6 and block copolyetheramides with hard segments of Nylon-6 and soft segments of poly (tetramethylene ether) were prepared. The impact strength of the blends was enhanced by the presence of the block copolyetheramides as compared to the Nylon-6. Different block copolyetheramides exhibited different effects on the impact strength which could be described as the difference in compatibility between the Nylon-6 and the Nylon-6 segments of the block copolymers. The difference in compatibility was verified by the investigations of TEM and DSC. As the caprolactam content of the block copolyetheramides increased, the compatibility between the Nylon-6 and the Nylon-6 segments of the block copolymers was enhanced and the blends exhibited a higher impact strength in general. The heat deflection temperature of the blends decreased as the polyether content (depending on the type and the content of the block copolyetheramide) of the blends increased. When the polyether content was less-than-or-equal-to 20 wt %, a small decrease in heat distortion temperature was found.