Top quark production cross section at the Tevatron

Preliminary results obtained by the CDF and D0 Collaborations on the top quark pair production cross-section in p pbar collisions at a center-of-mass energy of 1.96 TeV are presented. The measurements are obtained using various final states from top quark pair production and decays, and are based on data collected during years 2002-2004 of the Tevatron Run II.