In order to enhance the figure of merit ZT, gold nano-particles-bismuth telluride composites have been synthesized using the electro-chemical co-deposition and a significant improvement of thermoelectric properties has been achieved. The composite with 5 wt% of 5 nm-diameter gold nano-particles shows highest absolute Seebeck coefficient (similar to 380 mu V/K), lowthermal conductivity (similar to 0.5 W/m.K) and high figure of merit ZT (similar to 0.62) at room temperature. This ZT value is approximately forty times better than that of the as-deposited pure bismuth telluride film synthesized using the electrochemical deposition with the similar condition. (C) The Author(s) 2019. Published by ECS.