This catalogue of known Galactic supernova remnants (SNRs) is an updated version of the catalogues of Galactic SNRs presented in detail in Green (1984, 1988), in summary form in Green (1991, 1996, 2004), and on the Web (versions of 1995 July, 1996 August, 1998 September, 2000 August, 2001 December, 2004 January and 2006 April). (Note that version published in Green (1996) was produced in 1993.) This the 2009 March version of the catalogue contains 274 SNRs, and is based on results published in the literature up to the end of 2008. The basic summary data included in this catalogue for each SNR are its Galactic coordinates, RA and Dec (J2000.0), angular size, type, flux density at 1 GHz, spectral index, and any other names. Notes on these parameters, on possible remnants not included, and questionable SNRs listed in the catalogue are given in the full version of the catalogue on the Web. It should be noted that there are selection effects which apply to the identification of Galactic SNRs (e.g., Green 1991, 2004, 2005, 2009), so that care should be taken if these data are used in any statistical studies.