3D printing is currently recognized as a disruptive polymer processing technology. However, although recent research efforts have focused on the identification of the materials requirements for successful printing (physical, chemical, thermal and rheological properties), the commercial range of polymer filaments continues to be surprisingly limited. This is particularly noticeable when the aim is to add functionality to printed parts, such as thermal or electrical conductivity. Electrically conductive composites are attractive for several applications depending on their conductivity range. Examples are electrostatic dissipation (10-8 – 10-6 S.cm-1), electrostatic painting (10-6 – 10-4 S.cm-1), electromagnetic interference (EMI) shielding (10-3 – 10-1 S.cm-1) and lightning strike protection (>101 S.cm-1) applications1. Polymers with aromatic carbon backbone characteristically present excellent mechanical properties, high thermal resistance and may establish strong interactions with graphene-like surfaces via π-π stacking2. The present work reports the preparation of an electrically conductive thermoplastic composite by melt mixing using polyetheretherketone (PEEK), graphite nanoplates (GnP) and carbon nanotubes (CNT), its subsequent processing into conductive filaments and a few preliminary printing experiments. Characterization encompasses electrical conductivity, tensile strength and morphology. References: 1. Díez-Pascual, A. M., Naffakh, M., Marco, C., Ellis, G. & Gómez-Fatou, M. A. High-performance nanocomposites based on polyetherketones. Prog. Mater. Sci. 57, 1106–1190 (2012). 2. Yang, J. et al. Preparation and properties of poly (p-phenylene sulfide)/multiwall carbon nanotube composites obtained by melt compounding. Compos. Sci. Technol. 69, 147–153 (2009)