Purpose of the study: This study is undertaken to investigate the prevalence of smoking among dental undergraduates students in the University of Malaya, and to study the effects of smoking on the interproximal bone heights. Materials and method: A smoking habits questionnaire was distributed to the 299 Dental Undergraduate students of Year 2 to Year 5. Students were divided into groups of smokers (history of smoking for at least 1 year), former smokers (history of smoking and stopped more than 1 year) and non smokers (no smoking history). Two bitewing radiographs (left and right) were taken from 14 smokers and 5 former smokers. In addition, 14 students were randomly picked as control group, and their previously taken bitewing radiographs were collected. Interproximal bone loss defined as the distance (mm) from CEJ to the alveolar crest (AC) was measured using caliper, magnifier and metal ruler. Results: The prevalence of smokers and former smokers among dental students was 5.57% and 1.99%, respectively. Mean ± SEM of the CEJ-AC distance for smokers and non smokers was 1.063 ± 0.066 mm and 0.849 ± 0.050 mm, respectively. The difference was statistically significant between the smokers and non smokers (p<0.05). Mean ± SEM of bone loss among the smoker was 0.204 ± 0.066 mm. There was no satistically significant difference between former smokers and non smokers (p>0.05). Premolar is the most affected tooth in smokers, with a mean ± SEM of the CEJ-AC distance of 1.350 ± 0.102 mm. Conclusions: Smoking prevalence among dental undergraduate students was very low. Smokers have more bone destruction than the non-smokers.