The invention relates to an acid-dyeable polyamide fibre which can be obtained very reproducibly and unsusceptibly to faults during the production process. The fibre is characterized in that the amino end group content is less than 10 meq/kg. A very reproducible affinity for dyestuffy is obtained by copolymerization of a compound containing an acidic end group and having a basic nature. Compounds derived from melamine are particularly suitable.
