Meteosat Second Generation (MSG) is a series of 3 geo-stationary satellites developed and procured by the European Space Agency (ESA) on behalf of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The first satellite (MSG-1) was launched on August 29, 2002 by an Ariane 5 rocket. SEVIRI is the main MSG payload and produces 12 channels imaging in visible and IR range. The 8 Infrared Channels in the 3.9-13.4 mm band benefit from high radiometric performances thanks to the use of detectors operating at 95K and cooled by specifically designed passive radiator. During the commissioning phase, dedicated tests have been conducted to verify the SEVIRI functionality and performances. This paper presents briefly the SEVIRI design and highlights the correlation of data obtained in-flight by EUMETSAT with the ground predictions. A particular emphasis is put on the in-orbit evolution of the IR channel gains and on the instrument decontamination.