This paper describes the fabrication of polyimide-based microelectrodes with embedded fluidic microchannels. The thin-film structures combine for the first time a fluidic system with microelectrodes for recording and stimulation of biological signals on a flexible, implantable substrate. Microchannels were realized by a modified lamination technique and combined with a polyimide- platinum-polyimide sandwich structure. The probes can be used for monitoring cellular responses to various chemical stimuli delivered with high spatial precision.