In this study we examined the effects histopathologic and immunohistochemical of xylene inhalation in rats by using light microscopy. Adult wistar albino rats were used in this study. Eight rats were in control group and 8 rats were in the experimental group. The experimental group was exposed to 300 ppm formaldehyde 3-5 min/day, 5 days/week for 8 weeks. The lining epithelium of respiratory mucosa showed a loss of ciliated cells with metaplasia of goblet cells, hyperplasia of squamous cells and edema, inflamation in sub epithelial area). In the group treated xylene. Disruption of cell-cell contact was observed. Weak expression of E-cadherin was observed between cells. The vascular endothelium of capillaries and venoles showed intense immunostaining for VEGF.