Abstract: An improved oxygen sensing cell, especially of the polarographic type, is intended for use primarily in a gaseous environment. The cell has a cathode located at the bottom of the cell body. The cathode comprises a gold mesh electrode laminated to a thin-film sense membrane. The electrode is thus made immobile relative to the membrane, thereby improving the response time and providing for long-term sensor stability. The cell further has a guard electrode for the cathode. The guard electrode operates continuously and scavenges any oxygen molecules which are dissolved in the electrolyte and diffused towards the cathode. As a result, the dynamic range of the cell is substantially increased. The anode comprises a silver wire wound about a spool retained within the main cavity in the cell body. A p.c. board, as well as a compensation membrane, are resiliently retained at the top of the cell body. The body carries conductors for electrically connecting the p.c.