DENIS is a project to survey the all-southern sky simultaneously in three wavelength bands (Gunn-i 0.82 µm; J, 1.25 µm; and Ks, 2.15 µm) with limiting magnitudes 18.5, 16.5 and 14.0, respectively. The observations are performed with the 1m-ESO telescope at La Silla (Chile). The DENIS instrument is made up of a 3-channel camera built of commercially available detector arrays by the Observatoire de Paris and with major contributions from other European Institutes, notably: the IAS in Frascati, the Observatoire de Grenoble, the University of Innsbruck, the Observatoire de Lyon, and the IAC in Tenerife. The survey is carried out by observing strips of 30° in declination and 12 arcminutes in Right Ascension with an overlap of 2 arcminutes between consecutive strips. The observations started at the end of 1995 and have been completed on Sept. 9, 2001. The data are reduced in two consecutive steps, the image processing and source extraction, which are performed at the Institut d'Astrophysique de Paris. The position of a general extracted point source is provided with an accuracy better than 1 arcsec and its magnitude to better than 0.1 mag.Original acknowledgement for data: The DENIS project has been partly funded by the SCIENCE and the HCM plans of the European Commission under grants CT920791 and CT940627. It is supported by INSU, MEN and CNRS in France, by the State of Baden-Württemberg in Germany, by DGICYT in Spain, by CNR in Italy, by FFwFBWF in Austria, by FAPESP in Brazil, by OTKA grants F-4239 and F-013990 in Hungary, and by the ESO C&EE grant A-04-046.