This paper reviews recent efforts by authors' group to utilize electrochemical processes for formation, processing and gate control of III-V semiconductor nanostructures. Topics include precise photo-anodic and pulsed anodic etching of InP, formation of arrays of < 001 >-oriented straight nanopores in n-type (001)InP by anodization and their possible applications and macroscopic and nanometer-scale metal contact formation on GaAs, InP and GaN by a pulsed in situ electrochemical process, which remarkably reduces Fermi level pinning. All the results indicate that electrochemical processes can achieve unique and important results, which the conventional semiconductor technology cannot realize, anticipating their increased importance in future semiconductor nanotechnology and nanoelectronics. (c) 2005 Elsevier Ltd. All rights reserved.