This work presents the development of magnetic carbon nanotubes (MCNTs) from plastic solid waste (PSW). For this purpose, diverse catalytic nanoparticles based on Fe, Ni and Al were prepared by impregnation of alumina or co-precipitation of Ni, Fe and Al nitrate salts with NH4OH, followed by calcination at 800 ºC. These magnetic nanoparticles were then used as catalysts in the growth of carbon nanotubes by chemical vapour deposition in a tubular furnace using low-density polyethylene as carbon precursor and as representative polymer composing PSW. MCNTs were characterized by transmission electron microscopy (TEM) and X-ray diffraction. The morphology and dimensions of the MCNTs were observed by TEM, concluding that large multiwalled MCNTs were prepared with magnetic nanoparticles inside (spacing of ~0.2 nm) and with a carbon interlayer spacing of ~0.34 nm. In conclusion, the synthesis of MCNTs from polyolefins is evidenced and can lead to technological alternatives in the treatment of PSWs.