The use of fermented sugar beet pulp for making paper or cardboard is disclosed as well as a fermented sugar beet pulp composition produced according to a method which comprises the steps of (a) storing the sugar beet pulp under conditions suitable for lactic acid fermentation, particularly until the pH is less than around 5 and advantageously higher than around 3.5, to give fermented pulp, (b) diluting the fermented pulp, particularly until its dry matter content is of around 1-10 %, (c) mechanically processing the diluted fermented pulp to separate the parenchymal cells from the pulp and achieve a pulp size of less than around 1000 micrometers, and (d) optionally bleaching the fermented pulp from step (a) simultaneously with step (b), or bleaching the fermented pulp from step (c).