Maras Powder is a kind of smokeless tobacco widely used in lieu of cigarettes in the South-Eastern region of Turkey. In this study, we have evaluated micronuclei in buccal mucosa cells of habitual Maras Powder users. Therefore, we divided our subjects into three groups--smokeless tobacco users, smokers and non-smokers/non-users. The mean percentage of micronucleated (MN) cells was significantly higher in smokeless tobacco users and smokers than in non-smokers/non-users (P < 0.01) [corrected]. The mean percentage of MN cells was 1.86 +/- 0.26 in users and 1.99 +/- 0.30 in smokers. There was no difference between the mean percentage of MN cells in these two groups. In conclusion, the genotoxic effect of smokeless tobacco should be considered in addition to other known hazards.