The present invention relates to an improved process for preparing riboflavin of the B/C modification in granule form. Furthermore, the invention relates to the riboflavin preparation process wherein riboflavin of the A modification is (a) dissolved in aqueous mineral acid without treating the resulting riboflavin solution with activated carbon, (b) precipitated directly afterwards, steps (a) and (b) being carried out at a temperature in the range from 5 to 15.degree. C., and (c) dried by fluidized bed granulation; and wherein the riboflavin does not come into contact with the aqueous mineral acid solvent for longer than on average 4 hours.