Three categories of tobacco products were studied using electron paramagnetic resonance (EPR) spectroscopy: Cuban cigar brand name Montecristo, four international trademark cigarettes, and three types of Middle Eastern tobacco blends called Al-Moassal or Jurak. The Montecristo Cuban cigar is used as standard of high-quality tobacco. Mainly two EPR signals from all of the studied samples are observed: a very weak sharp EPR signal superimposed on a broad signal. The broad EPR signal is attributed to a manganese(II) complex. The intensity of the manganese(II) EPR signal is found to be related to the quality of the tobacco content. The sharp signal, which is characteristic of semiquinone radicals, is observed at room temperature, and its intensity increases drastically with temperature.