The long term effect of sulfur mustard (SM) exposure including, total and differential white blood cells (WBC), hematological parameters, pulmonary function tests (PFT), and respiratory symptoms (RS) in chemical war victims (CWV) exposed to SM 27-30 years ago were examined. Forty-six CWV and 42 control subjects with similar age from the general population were studied. Hematologic parameters, RS including; chest wheezing, night cough, night wheezing and cough, wheezing due to exercise (by Persian questionnaire), and PFT were assessed in all subjects. Total WBC count (p < 0.001), hematocrit, and mean corpuscular volume (MCV) were significantly higher (p < 0.05 and 0.001, respectively) but mean corpuscular hemoglobin concentration (MCHC) and the percent of monocyte were lower in veterans than control group (p < 0.001 and 0.01, respectively). All PFT values were also lower in CWV compared to control subjects (p < 0.001 for all cases). Maximal mid expiratory flow (MMEF) and maximal expiratory flow at 75% of forced vital capacity (MEF75) were the most affected PFT values in CWV and were 50% or lower of predicted values. All CWV reported respiratory symptoms, including; chest wheezing, night cough, night wheezing and cough, and wheezing due to exercise were higher in the veterans compared to control group (p < 0.001 for all cases). Increased total WBC count and RS but reduction in monocyte, MCHC, and PFT values were shown in CWV 27-30 years after exposure to SM. These results indicated profound hematologic (mainly WBC) and pulmonary effect of SM long time after exposure.