Nowadays, the use of tobacco biomass as an energy source is being valued. Therefore, it is important to know the processes that take place during combustion and pyrolysis, as well as the substances that are formed. In this work, we study the compounds obtained during the decomposition of NNN as a function of temperature under inert and oxidant atmospheres. Moreover, the effect of the addition of SBA-15 and MCM-41 is analyzed. Two different techniques, i.e., TG/FTIR (low heating rates) and EGA Py/GC/MS (high heating rates), are used. At low temperatures NNN is almost unaltered, but it is volatilized and dragged by the carrier gas. When increasing the temperature, decomposition takes place, with pyridines being one of the most abundant compounds observed. The main compound obtained during the pyrolysis are 3- pyridinecarbonitrile, myosmine and nornicotine, which are precursors of NNN. When NNN is mixed with SBA-15, the decomposition of the NNN nitrosamine is favored at low temperatures where the yield in pyridine compounds increases. The catalysts modify the temperature and intensity of the processes, especially under an oxidative atmosphere where the residue is oxidized, showing a third loss of weight. These materials modify the compositions of gases, mainly under an O2 atmosphere (3-pyridinecarbonitrile and myosmine showed the major effect). SBA-15 with fibrous morphology obtains the best reductions at pyrolysis conditions.