This entry comprises a brief introduction of microemulsion and a focused presentation of conductance of microemulsion, especially various aspects of its percolation in single and mixed surfactant systems. The mechanism of percolation (which broadly covers different models with special reference to droplet size, their clustering in ionic and nonionic water-in-oil (w/o) microemulsions, and interdroplet exchange rate involved in the percolation process), its theory, effects of oils and additives (with different physicochemical properties), and pressure on the process, and the related energetics of droplet association (or clustering) are presented and discussed. Both limitations and further trends of research in this emerging area have also been emphasized.