Tunability of electronic properties of semiconductors is vital for obtaining large efficiencies in thermoelectrics. The figure of merit for thermoelectric efficiency is defined as ZT =S2?T/k where S is the Seebeck coefficient and ? and k are the electrical and thermal conductivities of the material respectively. The electronic performance is determined by the powerfactor, S2? which can be shown to be directly related to the mobility and effective mass of the semiconductor. With large mobilities (65 cm2/V-s) and large conduction band effective mass (0.67m0) few-layer MoS2 samples provide a promising avenue for thermoelectrics. Our experiments demonstrate that the gate-tuned powerfactor in bilayer MoS2 can be as large as 8.5 mW/m-K2 which is twice as large as commercially viable Bismuth Telluride. We further discuss the origin of the large Seebeck Coefficient in single-layer MoS2. Our results open up new possibilities of using 2D materials for thermoelectrics.