Background: Pulmonary fibrosis could be a threat for the health society. Oxidative stress, inflammatory, and fibrotic factors have an important role in the pathology of pulmonary fibrosis. The inhibition of these factors is a central mechanism for lung fibrosis prevention and therapy. Objectives: According to Gemfibrozil (GEM) effects, such as antioxidative and anti-inflammatory effects, this study was designed to evaluate the effect of GEM in an animal model of pulmonary injury and fibrosis induced by Bleomycin (BLM). Methods: Experiments were done at 2 different time periods, 1 and 3 weeks in duration after BLM. In each time period, thirty rats were divided to 5 groups: 1, vehicle orally + saline Intratracheally (IT); 2, vehicle orally + BLM (IT) and 3 -5, GEM at the doses of 25, 50, and 100 mg/kg, orally + BLM (IT), respectively. Gem was administered 3 day before BLM and continued for one or three weeks. Results: At the end of both phases, 7th day and 21th day lung index and tissue collagen level were determined. Furthermore, macroscopic appearance and histopathological were analyzed. The results showed that gemfibrozil had beneficial effects in a dosedependent manner and best results were found in animals treated by 100 mg/kg of GEM. Conclusions: Finally, the current study concluded that GEM could be considered as a candidate in lung injury and fibrosis and could be used for improvement of lung damage and fibrosis in humans.