In recent years, with Additive Manufacturing (AM) technology, which is used in many different areas, it is possible to manufacture 3D parts in complex form more easily, inexpensively and quickly than conventional methods. Among the AM technologies, the most popular and inexpensive method is Fused Deposition Modelling (FDM). Recently there is growing interest in direct manufacturing of final ready for use parts using this technology. However mechanical properties of the FDM printed parts are the main constraint preventing the widespred application of FDM printed parts. In order to apply AM extensively in the manufacture of finished parts, there is a need for improvements in existing techniques and materials to meet the mechanical requirements of the load-bearing components. This paper, for the first time, investigates feasibity of manufacturing and FDM 3D printing of 6 mm long carbon fibre reinforced acrylonitrilebutadiene-styrene (ABS) composite filaments. The part strength is shown to be significantly improved with 6 mm long carbon fibre reinforcement with the flexibility and processability of the fibres is diminishing with increasing reinforcement content. It has also been determined that the print pattern significantly affects the mechanical properties.