For the ENVISAT validation different ground-based techniques have been used. MIPAS O3 profiles have been compared with data from different ground-based techniques such as FTIR, LIDAR, O3 sondes, and MWR. All instruments used are operated within the NDS (Network for the Detection of Stratospheric Change). These comparisons covering different techniques as well as different latitudes show a consistent picture. All MIPAS data used in this paper are processed with software version 4.53. In most cases the coincidence criteria are 1000 km in space and 12 hours in time, otherwise they are stated in the text. MIPAS O3 profiles measured before November 13, 2002 show an error in altitude assignment of about 1 to 1.5 km. MIPAS O3 profiles versus pressure are not affected by this. The update of the pointing characterization in the data processor as implemented on November 13 has clearly solved this problem. The MIPAS profiles agree quite well with ground-based data. The mean differences are within 10% in an altitude range of about 20 to 40 km. Below 20 km MIPAS tends to slightly overestimate the vmr while above 25 km MIPAS tends to slightly underestimate the vmr. However, more coincidences are needed for a more quantitative analysis.