Non-polymeric carbohydrates including glucose, fructose, and sucrose are major constituents in flue-cured and Oriental tobaccos. The compounds are also present in burley although at much lower levels. Other small carbohydrates as well as carbohydrate derived compounds such as various sugar acids are also present in tobacco. These compounds start decomposing at relatively low temperatures, around 150-155 °C. During tobacco processing, preparation of expanded tobaccos, as well as when tobacco is used in “heat not burn” type cigarettes, the tobacco is exposed to different degrees of heat, frequently higher than the temperatures where carbohydrates start decomposing. A systematic study applied to six types of tobacco was performed regarding the variation of the level of several sugars upon heating. These tobaccos included two flue-cured, two burley, and two Oriental tobaccos. The heating was performed for 5 min at 60 °C, 100 °C, 150 °C, and 200 °C. The analysis of sugars was performed using direct silylation followed by a GC/MS analysis. Together with sugars, other compounds were detected in the chromatograms. Since burleys have low levels of sugars and most of other tobacco components are more stable up to 200 °C, the burley composition appears to change very little with heating. On the other hand, the flue-cured and Oriental tobaccos show some decrease in sugars for heating up to 150 °C and a significant decrease when tobacco is heated at 200 °C.