The present study investigated the effect of both active and second hand smoking on Body Mass Index of adult smokers in rural areas of Chandigarh. The relationship of body mass index with smoking status was also assessed in current daily and intermittent smokers. The male subjects (N=240) of 20-30 years and 30-40 years age category were divided into four groups of 30 subjects each based on Global Adult Tobacco Survey Questionnaire, India as follows: Group 1 – Current daily cigarette smokers, Group 2 – current intermittent cigarette smokers, Group 3 – Second hand cigarette smokers and Group 4 – Nonsmokers (Control group). One way ANOVA test showed non-significant differences between and within all the groups in body mass index (F=1.11, p>0.05) in 20-30 years age category. In 30-40 years age category, significant differences (F=4.11, p<0.05) were observed between and within all the groups. Post hoc Scheffe test in 30-40 years category also revealed significant mean differences between current daily smokers and non-smokers. Karl Pearson’s correlation test showed a highly significant inverse linear relationship (p<0.001) between pack years and BMI in both current daily and intermittent smokers. Current smoking of moderate intensity has an effect to alter relative fatness (or BMI) of the body. There may be no substantial difference in BMI with moderate and light smoking as well as exposure to secondhand smoke (SHS) in younger adults. The greater the number of cigarettes smoked, the lower the adult smoker’s BMI in both current moderate and intermittent light smokers.