The aim of the Karlsruhe Tritium Neutrino experiment - KATRIN - is the direct (model-independent) measurement of the mass of the electron anti-neutrino [T. Thümmler, Introduction to direct neutrino mass measurements and KATRIN, Neutrino 2010 (Athens, Greece).]. For that purpose a windowless gaseous tritium source WGTS is used, with a tritium throughput of 40 g/day. In order to reach the design sensitivity of 0.2 eV/c2 (90% C.L.) the key parameters of the tritium source, i.e. the gas inlet rate and the gas composition, have to be stabilized and monitored at the 0.1 % level (1σ). Any small change of the tritium gas composition will manifest itself in non-negligible effects on the KATRIN measurements; therefore, precise methods to specifically monitor the gas composition have to be implemented. Laser Raman Spectroscopy is the method of choice for the monitoring of the gas composition because it is a non-invasive and fast in-line measurement technique. An overview of the current Raman activities at Tritium Laboratory Karlsruhe (TLK) is given.