The objective of this article was to show the role of cytokines in the pathogenesis of pulmonary fibrosis due to sulfur mustard gas inhalation. Eighteen veterans with mustard gas-induced pulmonary fibrosis and 18 normal patients were used as controls. Bronchoalveolar larvage (BAL) and analyses of BAL fluids for cellular and cytokine levels were performed. There was a significant difference in granulocyte colony stimulating factor (G-CSF) level in the BAL fluid of patients and the controls (p < 0.0001). Granulocyte-macrophage colony stimulating pulmonary fibrosis (GM-CSF) BAL levels were significantly increased in patients with pulmonary fibrosis (PF) in comparison with controls (p < 0.0001). Patients with PF have highly significant increases in IL-8 level compared to controls (87.94 ± 59.63 vs. 8.66 ± 6.97 g/mL⁻¹; p < 0.0001) as well. IL-8 and G-CSF levels in BAL fluid correlate only with the percentage and the absolute number of neutrophils of the BAL fluid in patients with PF (p = 0.02/p = 0.01; p = 0.01/p = 0.01; respectively). A significant correlation was found between GM-CSF BAL fluid level and the percentage and the absolute number of the BAL fluid eosinophils (p = 0.04 and p = 0.03). Neutrophils alveolitis, the presence of eosinophils, and higher concentrations of interleukin-8, G-CSF, and GM-CSF in BAL fluid are associated with the development of fibrosis in sulfur mustard victims.