The upgrade of the CMS tracker for Super-LHC

The CMS experiment at LHC is planning a major upgrade to adapt to increases in luminosity. It will be achieved in two stages, with a long shutdown about ten years after start-up. The new tracker should cope with several hundred interactions per bunch crossing and fluxes of thousands of charged particles emerging from 40 MHz collisions. CMS has identified a novel requirement, to utilise tracker data in the first level trigger. The motivations for the upgrade and recent progress are described.