Coaxial nanocables of gallium phosphide (Gal?) core with three different-typed single and double shells (i.e., silicon oxide (SiOx), carbon (C), and SiOx/C) were exclusively synthesized by the chemical vapor deposition method. The GaP/SiOx, nanocables were directly grown on gold-deposited silicon substrates. Deposition of C on the GaP nanowires and GaP/SiOx nanocables produces the GaP/C and GaP/SiOx/C nanocables, respectively. The outer diameter of the nanocables is < 50 nm. The thickness and crystallinity of the C outer layers were controllable by the growth conditions. X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy, and photoluminescence reveal that the outer layer formation reduces the surface defects of GaP nanowires. A great enhancement of the conductivity due to the C outer layers has been measured by the four-probe method. The growth process of these nanocables has been discussed on the basis of the vapor- liquid- solid mechanism.