Allogeneic blood transfusion leads to the infusion into the recipient of large amounts of antigens that may create conditions which are related to immune system modulation. The aim of this study was to determine the effects of smoking habit on vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6) levels in the plasma of blood donors. Blood samples from 170 consecutive blood donors was collected and analyzed for serum markers, while questionnaire data was collected. Serum cotinine levels were calculated for non-smokers, while serum cytokine IL-6 and VEGF concentrations were also calculated among 88 randomly selected subjects. Controlling for the donors age and gender, a strong tendency was found for smoking within 24 h of the blood donation to be associated with a higher VEGF concentration of the donated blood (ß = 141.13, p = 0.06), while the donor age was independently related to VEGF levels (p = 0.001). Additionally the IL-6 levels in the transfused blood were independently associated with the donors age (p = 0.001) and gender (p = 0.002) but not with their smoking status. Further research is needed so as to assess the need of updating blood donation guide lines to regulate the time intervals between the time from the last cigarette and blood donation.