It is of great interest to develop an efficient and reliable manufacturing approach that allows for the integration of microdevices each of which is optimally fabricated using a different process. We present a new method to achieve electrical and mechanical interconnects for use in heterogeneous integration. This method combines metal reflow and a self-aligned, 3-D microassembly approach. The results obtained so far include a self-aligned, 3-D assembly of MEMS to MEMS, post-processing which selectively deposited indium on 50 m-thick MEMS structures, and reflow tests of indium-on-gold samples demonstrating 15-45 m resistances for contact areas ranging from 100 to 625 m 2 . 3-D microassembly coupled with metal reflow allows for the batch processing of a large number of heterogeneous devices into one system without sacrificing performance. In addition, its 3-D nature adds a new degree of freedom in system design space. Downward scalability of the method is also discussed.