Background:bleomycin (BLM) is a chemotherapeutic agent having a wide use in the clinical field. Its most serious side effect is the life-threatening pulmonary toxicity.Objective:this study aimed to evaluate the role of captopril and erdosteine (ERD) in lung protection against BLM-induced injury in rats. Material and Methods:thirty-two rats were categorized into 4 equal groups. Group I: rats received distilled water. Group II: rats injected intaperitonealy with 0.5 mg of BLM sulphate dissolved in 0.5 ml saline twice weekly for 4 weeks. Group III: rats received BLM in a dose as in group II &ERD by a dose of 10 mg/kg/day orally, 2 days before BLM administration. Group IV: rats received BLM in a dose as in group IIand captopril with a dose of 5 mg∕kg orally for 4 weeks, 2 days before BLM administration. Results: rats treated with BLM revealed disturbance of lung structure. There were marked cellular infiltration and thickening in alveolar septa with wide variation in the diameter of alveoli. Blood vesselswere congested. Extravasation of blood into interalveolar septa was observed. Large number of vacuolated cuboidal cells was noticed. Large amounts of collagen fibers around the bronchioles and few collagen fibers in the interalveolar septa were detected. Sections of rats treated with BLM and ERD showed apparently normal lung structure but, some collapsed alveoli with thick septa were still noticed. Sections treated with BLM and captopril showed lesser structural improvement than ERD-treated sections.Conclusion: administration of captopril and ERD partially improved BLM-induced pulmonary fibrosis in rats.