The 2004–05 Regionalliga season was the eleventh season of the Regionalliga at tier three of the German football league system. It was contested in two geographical divisions with eighteen teams in the south and nineteen in the north. The champions, Eintracht Braunschweig and Kickers Offenbach, and the runners-up, SC Paderborn 07 and Sportfreunde Siegen, of every division were promoted to the 2. Bundesliga.