Background: We tried to understand whether or not there is a relationship between smoking and diabetes mellitus (DM). Methods: Current regular smokers for the last six months and age and sex-matched non-smokers were included. Patients with current alcohol consumption (one drink a day) and patients with malignancies or inflammatory, infectious, or devastating disorders were excluded. Results: The study included 247 smokers and 167 non-smokers. The mean age and body mass index (BMI) of smokers were 46.2 years and 26.6 kg/m2, respectively, and 70.0% of them were male. Although the mean weight, BMI, systolic and diastolic blood pressures, and hematocrit values were similar in both groups, fasting plasma glucose (FPG) and DM were lower in the smokers (102.3 versus 111.6 mg/dL, p=0.007 and 8.9% versus 14.3%, p<0.05, respectively). Similarly, high density lipoproteins (HDL) were lower in the smokers, again (40.9 versus 44.0 mg/dL, p<0.05). On the other hand, triglycerides (163.1 versus 151.3 mg/dL, p<0.05) and low density lipoproteins (LDL) (123.8 versus 117.5 mg/dL, p<0.05) were higher in the smokers. Parallel to triglycerides and LDL, erythrocyte sedimentation rate (ESR) (10.6 versus 9.3 mm/h, p<0.05) and C-reactive protein (CRP) (2.3 versus 2.0 mg/L, p<0.05) were also higher in them. Conclusion: Smoking-induced low-grade inflammation on vascular endothelium in whole body may terminate with the endothelial dysfunction, accelerated atherosclerosis, end-organ insufficiencies, early aging, and premature death. FPG and HDL may be negative whereas triglycerides, LDL, ESR, and CRP positive acute phase reactants terminating with lower prevalence of DM but higher incidence of dyslipidemia in smokers. Key words: Smoking, fasting plasma glucose, diabetes mellitus, high density lipoproteins, triglycerides, low density lipoproteins, dyslipidemia