A new process, based on the micro-co-extrusion of preceramic precursors, has been studied for manufacturing ceramic microelectrodes to be used in biomedical applications. Commercially available silicon polymers were applied and proper doping resulted in electrically conductive ceramic filaments. Chemical reticulation and high-temperature pyrolysis were applied to convert the polymeric resins into Si-O-C ceramic materials. Circular microelectrodes were manufactured with diameters between 100 microm and 5 mm with a different number of inner conductive lines (from 1 to 80). The flexural strength of the filaments depended on the outer diameter size; doping with carbon black produced filaments with an average conductivity of approximately 0.4 S/cm for a 50% weight carbon black load. The results achieved by in vitro studies confirmed a good biological performance of Si-O-C ceramic structures with both hard and soft tissue cell models.