Raised myeloperoxidase (MPO) serum levels are associated with endothelial dysfunction and cigarette smoking is a risk factor for cardiovascular diseases. Since myocardial infarction is associated with leukocytosis and smokers present increased levels of neutrophils, here we hypothesized that the levels of serum MPO in smokers could be also raised. We carried out a study on sixty eight adult healthy volunteers. The control group consisted of thirty four non-smokers and the test group was thirty four heavy smokers. The hemogram, interleukin-8 (IL-8) and MPO serum levels were measured. Neutrophil, monocyte and lymphocyte counts were higher (p < 0.05) and the serum levels of interleukin-8 (IL-8) and MPO were fourfold higher in smokers than in non-smokers (n = 34, p < 0.05). This result correlated perfectly with the increased neutrophil count and IL-8 serum level that characterize smoking subjects. We propose that the high level of serum MPO could be directly involved in the higher prevalence of coronary artery diseases among heavy smokers.