Electrical conductive nanostructures made of nanofibers of poly (amide 6) (PA6) with carboxyl functionalized multiwall carbon nanotubes (MWCNTCOOH) and anchored MWCNTCOOH were produced. The nanotubes were surface activated with carboxyl groups, dispersed in formic acid and added to a formic acid solution of PA6. The mixture was electrospun by applying a voltage of 30 kV; afterwards, the nanofiber's mats were immersed in an aqueous dispersion of MWCNTCOOH containing a nonionic surfactant. The chemical structure, morphology, thermal stability, and electrical conductivity of the nanostructures were evaluated by UV spectroscopy, scanning (SEM), and transmission electron microscopy (TEM), thermal gravimetric analyses (TGA) and volumetric conductivity measurements. The efficiency of the functionalization was confirmed by the UV peaks in the range between 220 and 250 nm (corresponding to a carbonyl group conjugated with a carbon-carbon double bond). SEM and TEM micrographs showed the pullout of the MWCNTCOOH from the nanofibers and the formation of a stable, percolated, and anchored MWCNTCOOH network on the nanofibers due to the anchoring of the MWCNTCOOH from the surfactant solution on the MWCNTCOOH of the nanofibers. The coated nanostructures had higher thermal stability and higher electrical conductivity than the noncoated ones, showing the efficiency of this simple procedure. POLYM. ENG. SCI., 55:1263–1272, 2015. © 2015 Society of Plastics Engineers