The Large Quasar Astrometric Catalog (LQAC) ------------------------------------------- The huge and increasing number of quasars reckoned from various sky surveys leads to a large quantity of data which brings various and inhomogeneous information in the fields of astrometry, photometry, radioastronomy and spectroscopy. In Souchay et al. (2009), we gather the 12 largest quasar catalogues (4 from radio interferometry programs, 8 from optical surveys), and we carry out systematic cross-identifications of the objects. Informations concerning u, b, v, g, r, i, z, J, K photometry as well as redshift and radio fluxes at 1.4 GHz, 2.3 GHz, 5.0 GHz, 8.4 GHz and 24 GH are given when available. A small proportion of remaining objects, not reckoned by the 12 catalogues and included in the Veron-Cetty & Veron quasar catalogues, are added in the compilation. The LQAC contains 113,666 quasars. We discuss the external homogeneity of the data by comparing the equatorial coordinates, the redshifts and the magnitudes of objects belonging to different catalogues. At last we use up-to-date cosmological parameters as well as recent models for galactic extinction and K-correction in order to evaluate the absolute magnitudes of the objects.