SCIAMACHY data processing generates products on various levels as required by the user community. These products are either produced in the ENVISAT Payload Data Segment as operational products or by science institutes as scientific products or value-added products. Operational processing occurs in two steps-level 0-1b and level 1b-2. In both steps different timescales may apply-near-realtime, fast delivery or offline. Level 0-1b processing generates geolocated and calibrated radiances from the raw atmospheric measurements, as well as from measurements for calibration and instrument monitoring. The algorithms convert measured signals into calibrated radiances. Therefore a sequence of calibration steps has to be applied starting with correcting the memory effect and non-linearity and ending with applying the radiometric instrument response. Particular attention has to be given to the correction of polarisation and degradation. The goal of level 1b-2 processing is to provide geophysical parameters such as column densities and profiles from trace gas species as well as cloud and aerosol parameters. Nadir measurements permit retrieving total column densities or cloud and aerosol parameters. From limb observations height resolved profiles of atmospheric parameters can be inferred. Together with the scientific and value-added products the SCIAMACHY data can serve a wide range of applications.