This paper reports results from electrical and thermal conduction measurements carried out on the DNA-gold composite for which the overall conduction is shown to be dominated by the DNA rather than the discontinuous gold coatings. The electrical and thermal conductivities of the composite were about 14 S/cm and 150 W/(m K) at room temperature, respectively. The resulting value of 3.6 x 10(-4) W ohms/K(2) for the Lorentz number indicates that thermal transport in the DNA is phonon-dominated and that the molecular vibrations play a key role in both electrical and thermal conduction processes of DNA molecules.