For every satellite experiment, it is extremely important to perform a thorough validation of the geophysical data products to guarantee a correct assessment of the capabilities and performances of the satellite experiment. IASI on METOP-1 will be the first Fourier transform infrared (FTIR) spectrometer of the METOP series to be launched. With METOP the emphasis is on the meteorological data products. However, this project will support the expectations of the atmospheric chemistry community who is very interested in the exploitation of the IASI spectra for deriving additional geophysical data products. Expected IASI data products are total columns and information as to the vertical distribution of the following gaseous species: CO, O3, HNO3, N2O and CH4. These gases play key roles in tropospheric chemistry and climate. This project will use independent correlative data at 11 stations worldwide to validate the before mentioned IASI products, while covering all major latitude bands. Recently developed inversion strategies for the ground-based FTIR data will be applied to provide correlative data of the highest possible quality for the present validation purposes.