Experiments have been conducted to investigate the effect of the degree of plastic deformation on the electrical resistance and thermal conductivity of Al-Mg- Si (6063) alloy. Thirty six samples of the 6063 alloy were used in all for the experiments (three samples constituted a group and twelve groups were instituted in the experiment with each group corresponding to a particular degree of deformation). Eleven groups were cold deformed plastically by subjecting the groups to different percentages of cold work starting from 5% to 55%, with 5% intervals. It was observed that there was no appreciable increase in the electrical resistance of the alloy as the degree of deformation increased. However, cold deformed 6063-Aluminium alloy appeared to be thermally unstable as the degree of plastic deformation increased. It was concluded that plastic deformation has no deleterious effect on the electrical resistance of the alloy but rendered the material thermally unstable in terms of thermal conductivity.