Nano-dispersed ZrO2/CoSb3 composites of various composition were prepared by uniaxial hot pressing of nano-sized powders of thermoelectric CoSb3 intermixed with ceramic nano-powders. The phase purity, the niicrostructure, and the temperature dependent transport parameters of the composites were investigated. Non-dispersed samples from nano-sized CoSb3 powders show higher electrical conductivity compared to melt-grown material which is attributed to the presence of a small excess of metallic Sb, but they exhibit lower thermal conductivity due to the fine-grained structure. Addition of 5 at.-% ZrO2 enhances the ratio of electrical to thermal conductivity, whereas hardly affects the See-beck coefficient. In this manner the nano-dispersion method provides an effective approach to improving the materials thermoelectric performance.