The aim of the study is to evaluate if occupational exposure to urban stressors could cause alterations in red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean cell volume (MCV), mean cell hemoglobin (MCH), mean corpuscular hemoglobin concentrations (MCHC) in traffic police compared to a control group. 694 subjects were included in the study: 347 traffic police and 347 controls matched by sex, age and length of service after excluding the subjects with the principal confounding factors. The levels of RBC, HGB, HCT were significantly higher in male (respectively p<0.001, p<0.05, p<0.01) and in female (respectively p<0.05, p<0.001, p<0.01) traffic police than in controls. The authors hypothesise that occupational exposure to urban stressors in traffic police can alter hemopoietic system.