Ozone volume mixing ratio (VMR) profiles are measured by the Michelson Interferometer for passive atmospheric sounding (MIPAS) on ENVISAT. The data sets produced by the science data processor at Institut für Meteorologie und Klimaforschung (IMK), Germany are compared with those obtained by halogen occultation experiment (HALOE) on UARS and by sub-millimetre radiometer (SMR) on ODIN. For the stratospheric measurements taken during September/October 2002, the three instruments show reasonable agreement, with global mean differences within 0.1–0.3 ppmv. The typical zonal mean differences are of 0.4 ppmv for HALOE and 0.6 ppmv for SMR (4–6%) in the ozone VMR peak region at 25–30 km near the equator, though larger differences of 0.8–1 ppmv (8–10%) are also observed in a small latitude–altitude region in the tropic. A positive bias of about 0.2–0.4 ppmv in the MIPAS data in the 35–40 km region has also been found. Further studies are under way to explain these differences.