A μ-porous silicon (μPS) gas sensor based on interdigitated μ-electrodes (IDuE's) has been designed and developed. μPS obtained by means of electrochemical anodization of a p-type silicon (c-Si) wafer was used as active layer. The μPS layers are supported by the bulk of the c-Si wafer. Interdigitated μ-electrodes, which work as transducers, were deposited on the uPS surface by means of gold evaporation using shadow mask technique. Different IDμE's, with different geometries and dimensions have been deposited. Additionally, different conditions of μPS formation, as i.e. electrolyte concentration, current density and anodization time, were used in order to obtain different actives layers with different absorption capabilities. Clear responses to organic vapors such us ethanol have been obtained.