Amperometric oxygen sensors employing non-platinum electrocatalyst made from pyrolyzed cobalt-tetramethoxy-phenylporphyrin (CoTMPP) are described. A technique for the preparation of an oxygen working electrode with catalyst from a pressed matrix (tablet) is presented. This technique allows manufacturing numerous electrodes from the same pressed tablet, all of which demonstrate good reproducibility of their parameters. Glucose biosensors are constructed using this oxygen electrode as a basic transducer for amperometric detection of oxygen consumption. The enzyme (glucose oxidase) is held in a micro-bioreactor (face side closed by a Silastic coated polycarbonate membrane) in which the oxygen sensor is immersed. Linearity of the sensor response to glucose concentrations up to 16 mM is reported. Sensors demonstrated a stable signal (varying within ±5% of its average value) during 15 days of continuousin vitroglucose monitoring at 37°C.