During the last decade, hybrid inorganic/organic thermoelectrics have emerged as a relevant alternative for low temperature waste heat harvesting applications (T<500 K)[1]. Carbon nanotubes/thermoplastic polymer based nanocomposites represent especially an attractive solution[2]. Among thermoplastic polymers, poly(vinylidene fluoride) (PVDF) appears interesting: it is a semi-crystalline polymer that exhibits dielectric, ferroelectric and piezoelectric properties, extremely dependent on the nature of the crystal phase (polar or non polar). Since nanofiller incorporation can promote one of the two polar phases, piezoelectric properties of multi-walled carbon nanotubes (MWCNT)/PVDF nanocomposites have been intensively studied. In this work, the through-plane thermoelectric properties of bulk MWCNT/PVDF nanocomposites, prepared by a simple solution mixing process, have been investigated with various contents of MWCNT, up to 50 wt%. Hence ZT has been improved, at room temperature, by several orders of magnitude, up to 1.5 10-5. The impact of thermal treatment, and thus the nature of the crystal phase of PVDF, has been evidenced for the first time, using WAXS, IR spectroscopy and DSC[3]. Subsequently, in-plane thermoelectric properties of thin films MWCNT/PVDF nanocomposites, prepared by drop casting from the same solutions as for bulk composites, have been investigated thanks to the Linseis thin film analyser (TFA), implementing the 3omega technique for thermal conductivity measurements. ZT values appear significantly better, reaching 5.0 10-4 at room temperature, and exceeding 1.0 10-3 at 150°C. The introduction of single-walled carbon nanotubes (SWCNT), instead of MWCNT, is expected to improve these values of one order of magnitude again, which would allow to reach 0.01 at room temperature. These results evidence the strong anisotropy of thermoelectric properties of composites and the interest of thin films. This study confirms the benefit of carbon nanotubes/thermoplastic polymers for low temperature thermoelectric applications and the scope for significant further improvements.