Hexanoic acid (HA) doped polyaniline (PAni) nanocomposites which consist of different contents of untreated double wall carbon nanotubes (u‐DWNT) and carboxyl treated DWNT (c‐DWNT) with titanium dioxide nanoparticles were successfully prepared using template‐free method. Fourier transform infrared, ultraviolet‐visible and X‐ray diffractometer spectra clearly confirmed the chemical structure of PAni nanocomposites. Thermal stability, morphology, conductivity, magnetic properties and reflection loss of PAni nanocomposites were characterized by thermogravimetric analyzer, field emission scanning electron microscope, four‐point probe, vibrating sample magnetometer and microwave vector network analyzer, respectively. From this study, it is shown that electrical conductivity of PAni nanocomposites with u‐DWNT possessed higher conductivity (1.23 × 10–1 to 1.31 × 100 S/cm) compared to c‐DWNT (3.43 × 10–2 to 4.48 × 10–1S/cm). PAni/HA/TiO2/DWNT nanocomposites with 20% of c‐DWNT have been covered by PAni layers to form the highest amount of nanorods/nanotubes. Hence, it shows high heterogeneity that will enhance the dielectric permittivity and contribute to a more disordered motion of charge carriers along the PAni backbone. Therefore, it will eventually contribute to good microwave absorption and potentially apply as an efficient electromagnetic interference shielding material in cell phones. POLYM. COMPOS., 39:1283–1291, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]