Electrochemical approaches for the fabrication of functional micro-nano structures and devices were comprehensively described primarily on the basis of the results obtained from previous studies conducted by the author's group with the aim of demonstrating the potential for achieving further precise controllability. First, a theoretical study was conducted for investigating the processes, mainly focusing upon electroless deposition to present an approach for analyzing its reaction mechanism from the molecular level. These approaches could be powerful tools for elucidating the overall process and could contribute toward achieving the precise design of processes. Second, some experimental approaches for achieving the precise control of micro-nano fabrication of functional structures, such as maskless and electroless fabrication of metal nano-patterns, lateral enhanced electrodeposition to form ultrathin layers, as well as the nanostructures for various devices by through-mask electrochemical deposition, were introduced to demonstrate high capability of the processes for nanoscale fabrication in various applications.