Thermoelectric microgenerators and microcoolers are becoming technologically important for microelectromechanical systems (MEMS), but the conventional cutting and assembling techniques have limitation in miniaturizing the dimensions of thermoelectric devices to the micrometer order. We have combined MEMS technology and materials processing into a novel process to manufacture thermoelectric micro-modules with densely aligned fine-scale and high-aspect-ratio P-N elements. Our process consists of the following major steps: (1) micromachining a silicon mold; (2) filling the mold with thermoelectric materials; (3) connecting P-and N-type elements and assembling the whole module. By using the present process, Bi-Sb-Te system thermoelectric elements of 300m height and 40m cross-sectional width can be fabricated successfully.