Smoking is recognized as a health problem worldwide and there is an established tobacco epidemic in SaudiArabia as in many other countries, with tobacco users at increased risk of developing many diseases. This crosssectional study was conducted to assess the prevalence of oral mucosal, potentially malignant or malignant,lesions associated with tobacco use among a stratified cluster sample of adults in Jeddah, Saudi Arabia. A samplesize of 599 was collected and each participant underwent clinical conventional oral examination and filled aquestionnaire providing information on demographics, tobacco use and other relevant habits. The most commonform of tobacco used was cigarette smoking (65.6 %) followed by Shisha or Moasel (38.1%), while chewingtobacco, betel nuts and gat accounted for 21-2%, 7.7%, and 5% respectively. A high prevalence (88.8%) of softtissue lesions was found among the tobacco users examined, and a wide range of lesions were detected, about50% having hairy tongue, 36% smoker’s melanosis, 28.9% stomatitis nicotina, 27% frictional keratosis, 26.7%fissured tongue, 26% gingival or periodontal inflammation and finally 20% leukodema. Suspicious potentiallymalignant lesions affected 10.5% of the subjects, most prevalent being keratosis (6.3%), leukoplakia (2.3%),erythroplakia (0.7%), oral submucous fibrosis (0.5%) and lichenoid lesions (0.4%), these being associated withmale gender, lower level of education, presence of diabetes and a chewing tobacco habit. It is concluded thatsmoking was associated with a wide range of oral mucosal lesions , those suspicious for malignancy being linkedwith chewable forms, indicating serious effects.