The author analyses possible solutions of the problem connected with the census of 125/124 BC, which were suggested in western historiography. They were mostly put forward in the 19th century and still remain plausible, since there is no decisive arguments in favour of any of them. The question of the criteria used for enlisting citizens cited by Roman authors is among the central ones. After the publication of P. Brunt’s «Italian Manpower 225 BC–AD 14» the prevailing opinion is that Roman census registered all the male population sui generis, including cives sine suffragio, libertini and proletarii. This point of view was challenged by E. Herzog who found only Roman assidui in the lists. The author undertakes a critical analysis of both opinions as well as of the arguments supporting them and tries to reconstruct the census of 125/124 BC.