One of the nine instruments on-board the polar-orbiting environmental satellite ENVISAT is the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument. This paper presents validation results of GOMOS ozone profiles (v6.0a) from comparisons to microwave radiometer, balloon ozonesonde and lidar measurements worldwide. Thirty-one instruments/ launch-sites at twenty-five stations ranging from the Arctic to the Antarctic joined in this activity. We identified 3,713 useful collocated observations that were performed within an 800-km radius and a maximum 20hours time difference of a satellite observation, for the period June 2002 and March 2003. These collocated profiles were compared and the results were analyzed for possible dependencies on several geophysical (e.g., latitude) and GOMOS observational (e.g., star characteristics) parameters. In a dark atmospheric limb the GOMOS data agree very well with the correlative data and between 20- to 61-km altitude their differences only show a small (2.5%) insignificant negative bias with a standard deviation of about 14%. This conclusion is demonstrated to be independent of the star temperature and magnitude, and the latitudinal region of the GOMOS observation.