This study was conducted to determine the sidestream smoke concentration, nicotine, tar, and CO, by the characteristics of tobacco leaves and their combinations. 20 kinds of tobacco leaves and 15 types of their combinations were selected for this study. After collecting the sidestream smoke by fishtail chimney, the concentrations of nicotine, tar, and CO in sidestream smoke were analyzed. Variation in nicotine concentration of sidestream smoke among tobacco leaves and their combinations was as much as 9-times. Heavy leaves and burley leaves were higher in nicotine concentration than light leaves and flue-cured leaves, respectively, the reconstituted tobacco leaf had the minimum concentration of nicotine. Tar concentration of sidestream smoke also was changed by the characteristics of tobacco leaves and their combinations. As the american C4F had the maximum concentration of tar in sidestream smoke, the reconstituted tobacco leaf showed the minimum concentration. Blending 50 % flue-cured B1-0 plus 50% burley B1-T grade showed the highest value in the nicotine concentration. Also, in case of adding B3K and izmir tobacco leaves, the nicotine concentration was decreased. The tar concentration in the sidestream smoke increased as increasing the amount of flue-cured heavy leaf. The CO concentration was not so much Changed by the characteristics of tobacco leaves and their combinations.