Additive manufacturing is an emerging technology which could potentially initialise another industrial revolution. Important advances in the optimization of the 3D printers have been carried out in the last 10 years(1). One of the most promising techniques for rapid design and prototyping is Fused Modeling Deposition (FDM) due to the facility to extrude thermoplastic polymers in the form of filaments2. The 3D market demands a wide range of polymer materials to be printed in different applications such as automotive, aeronautics, food packaging and consumer goods1 etc. Thermoplastics reinforced with carbon nanomaterials shows an interest for the automotive or aeronautic sectors due to high mechanical, thermal and electrical properties(2). One of the main goals focuses on the optimization of the industrial processing of these polymers composites and their adaptation to the 3D specification printing. In this work we present a straightforward non-wet route to fabricate PLA/MWCNTs composites filaments by small-scale industrial extrusion process to be used in 3D printers and the studies of mechanical properties of the developed filaments. MWCNTs were first functionalised following the procedure described(3) to produce the composite with the aim to increase the nanomaterials dispersion in the polymer matrix. Pre-dispersion of MWCNTs in PLA was carried out by using a mechanical milling process. Subsequently the pre-dispersion was extruded into a filament of 1.75 mm mean diameter. Preliminary results show an enhancement of tensile load (8-10%) on filaments reinforced with non-functionalised MWCNTs and even more (16-18%) when these filaments are made of functionalised MWCNTs. [1] “A third industrial revolution,” The Economist, (2012) [2] R. H. A. Haq, et al. Applied Mechanics and Materials. 8-12, 465-466 (2014). [3] S. Mali et al. Beilstein J Nanotechnol. 7, 1260–1266 (2016)