The Planck Early Release Compact Source Catalogue (ERCSC) is a list of all high reliability sources, both Galactic and extragalactic, derived from the first sky coverage. The data that went into this early release comprise all observations undertaken between 13 August 2009 and 6 June 2010, corresponding to Planck operational days 91-389. Since the Planck scan strategy results in the entire sky being observed every 6 months, the data considered in this release correspond to more than the first sky coverage. The source lists have reliability goals of 90% across the entire sky and > 95% at high Galactic latitude. The goals on photometric accuracy are 30% while the positional accuracy goal translates to a positional root mean square (RMS) uncertainty that is less than 1/5 of the beam full width at half maximum (FWHM). ref.: "Planck Early Results: The Early Release Compact Source Catalog" (ADS BibCode: 2011arXiv1101.2041P)