A perfectly homogenous melt is one of the prerequisites towards meeting increasingly strict quality requirements in the injection moulding. Melts can display heavy inhomgeneities downstream of the screw. including radial temperature differences and irregularities in pigment or additive distribution. This can lead to colour striation. staining, and discrepancies in the weight of products. In the injection moulding the homogeneity of melts after they leave plastifying unit is often inadequate. It is recommended to use static mixing units in the flow channel between the plastifying unit and the nozzle to improve homogenization. In this work we studied the influence of melt blender, Sulcer SMK X mixer, on temperature homogenization and colour distribution in the injection moulding of acrylonitrile butadiene styrene copolymer (ABS). Series of experiments were carried out with and without mixer on the Ferromatic Milacron F40 injection moulding machine. The mixer was located in front of the nozzle. The design of experiment technique was applied to minimize the number of required experiments, Barrel temperature, concentration of masterbatch, injection speed and cycle time were varied and quality of products tested by spectophotometric measurements of colour difference and mass measurements. The results proved that introduction of Sulzer mixer had great impact on product aesthetic quality due to better temperature homogenization and colour distribution. Optimization of the process parameters has been done. Barrel temperature was reduced from 2350C to 2270C and this resulted in shorter cycle time of product production. This also shortened the down time of the machine in the case of mould change or maintenance. The better colour distribution. measured by colour difference of standard and product, was obtained with the Sulcer mixer.