Binary logic devices constructed using moving mechanical components at microscale can be useful in harsh working environments where their electronic counterparts would fail. This paper demonstrates a novel design, extensive analysis, and development method of a micromechanical NOT gate and analyzes important issues in further development of mechanical logic circuits. The proposed NOT gate uses parallelogram flexures and flexure beam hinges to realize the logic without effects of friction. Extensive finite element(FE) analysis, carried out using ANSYS, enables us to arrive at the final design dimensions. We introduce a new term "Energy Transmission Ratio (ETR)" specific to flexure mechanism-based transmission systems and further FE analysis brings out interesting property that ETR has an optimal value forgiven flexure geometry. This result can be useful while connecting several logic gates to develop mechanical logic circuits. A graphical procedure for analysis of such connections is outlined based on our FE results. Finally, the proposed NOT gate is fabricated with SU-8 and demonstrated working successfully. Copyright © 2007 by ASME.