The SSC has been responsible, on behalf of ESA, for the construction of the XMM-Newton Serendipitous Source Catalogues. To date, there have been six releases of the (EPIC) X-ray catalogue: 1XMM, in April 2003, 2XMMp in July 2006, 2XMM in 2007 (2XMMp was an interim version of the more complete and extensive 2XMM catalogue), and two increments to 2XMM, i.e. 2XMMi in August 2008 and 2XMMi-DR3 in April 2010, and 3XMM-DR4 in July 2013. Production of the catalogues involves collation of archived, processed products (or a bulk reprocessing of all the data when major software and calibration changes have accumulated), the selection of suitable public datasets, screening and verification of the associated data products, compilation of the catalogue from the source lists of the individual observations and auxiliary information, scientific validation of the catalogue, and making the catalogues and documentation publicly available to the scientific community, in close collaboration with ESA. A number of added-value products, such as image thumbnails and summary web-pages for each source are also generated separately. Each catalogue release uses as many of the publicly available datasets as possible, though some observations are excluded for various reasons, e.g. very low exposure, or cases with processing or pathological problems.