Background: The many ill effects of cigarette smoking have been proven in many studies. This includes the various parameters in blood also. The fact that white blood cells or leucocytes are indirectly associated with heart disease and cancer is also well established. Aim: This study was done to compare the total and differential leucocyte count of adult male smokers and non-smokers and to determine the correlation between the number of pack-years and the total leucocyte count in smokers. Materials and Methods: This study incorporates the analysis of 100 Males of the same socio-economic status belonging to the age group of 25-50 years. Of these 100 men, 50 men were smokers and 50 men were non-smokers. The total leucocyte count and the differential leucocyte count were estimated. Results: The total leucocyte count and the differential count of lymphocytes were significantly higher in smokers (p = 0.002 and 0.003 respectively) compared to non-smokers, although within the normal range. The differential count of neutrophils was higher in non-smokers compared to that of their smoking counterparts (p value < 0.005), although within the normal range. We could also find a positive correlation (r value = 0.379) between the total leucocyte count and the quantity of cigarettes smoked. Conclusion: This study has revealed the total leucocyte count and the differential count of lymphocytes in smokers was significantly higher compared to non-smokers, although within the normal range and that there was a positive correlation between the quantity of cigarettes smoked in terms of pack-years and the total leucocyte count of the smokers.