The present invention provides an indium-doped Co.sub.4Sb.sub.12 skutterudite composition in which some Co on the cubic lattice structure may be replaced with one or more members of the group consisting of Fe, Ni, Ru, Rh, Pd, Ir and Pt; some Sb on the planar rings may be replaced by one or more members of the group consisting of Si, Ga, Ge and Sn; and a second dopant atom is selected from a member of the group consisting of Ca, Sc, Zn, Sr, Y, Pd, Ag, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The composition is useful as a thermoelectric material. In preferred embodiments, the composition has a figure of merit greater than 1.0. The present invention also provides a process for the production of the composition, and thermoelectric devices using the composition.