Blends of aliphatic polyamide PA 46 and aromatic polyamide PA 61 were obtained by coprecipitation from a common solvent and by melt mixing using a mini-extruder. The polyamides were found to be fully miscible by both blending methods. However, there are large differences in crystallization and melting behaviour when the blends obtained by the two methods of blending are compared to each other. This can be ascribed to the occurrence of transamidation processes during the melt mixing of the homopolyamides resulting in the formation of block copolyamides composed of crystallizable and non-crystallizable segments. The extent of the transreaction processes is dominated by the extrusion temperature and the extrusion lime. Increasing one of these processing parameters will enhance the transamidation reactions and shorten the crystallizable segment lengths. This will be reflected in a decreasing crystallization rate and lower melting points of the melt-mixed blends.