Development of new hybrid multi-walled carbon nanotubes (MWCNT) and conducting polymer has been studied due to these materials versatility. The knowledge of thermal properties is essential to evaluate the hybrids applicability, mainly in optoelectronic devices. In this work, chemical modifications was performed on the surface of MWCNT through microwave reaction, due to a shorter reaction time, less use of organic solvents and thionyl chloride free (high toxicity reagent). Subsequently, a new hybrid MWCNT@P3HT was obtained by in situ polymerization of poly (3-hexylthiophene) in the modified MWCNT, covalently linked. Kinetic study of thermal degradation was performed employing artificial neural network and isoconversional treatment, Friedman (FR) and Vyazovkin methods. The activation energies of MWCNT and MWCNT@P3HT thermal decomposition were determined and showed a significant increase in thermal stability for the hybrid. The activation energy for the MWCNT@P3HT is almost four times greater than the pure one, around 454.9 kJ mo1(-1).