Although there is cast iron evidence for a massive neutrino, obtained through the observation of neutrino oscillations, the absolute neutrino mass scale is yet unknown. Di fferent approaches are pursued to fix this parameter, which is of importance for particle physics and cosmology. In contrast to the investigations of neutrinoless double beta decay and cosmological observations, single beta decay experiments allow for a direct, model-independent access to the neutrino mass scale. The next generation large-scale tritium beta decay experiment KATRIN (Karlsruhe Tritium Neutrino experiment) is designed to determine the anti-electron neutrino mass with a sensitivity of 200 meV/c2 (90% C.L.). It is currently being assembled at the Karlsruhe Institute of Technology, with a planned start of tritium operation in 2016. The seminar covers an overview of the di fferent approaches to the absolute neutrino mass scale, focusing on the KATRIN experiment. An introduction to the working principle of KATRIN as well as an insight into the current experimental status, focusing on the recently commissioned spectrometer and detector section, will be given.
