The purpose of this study is to describe the radiologic manifestations of paraquat-induced pulmonary damage, with special emphasis on the sequential changes seen with this condition. Paraquat is a herbicide that has toxic effects on the lungs, liver, and kidneys. Progressive respiratory failure is a frequent cause of death. We analyzed retrospectively 42 patients with a history of paraquat ingestion and abnormal findings on chest radiographs. Radiographic changes during the first week after ingestion included diffuse consolidation (26/39), pneumomediastinum with or without pneumothorax (15/39), and cardiomegaly with widening of the superior mediastinum (8/39). Small cystic and linear shadows began to appear at the end of the first week and were the preponderant parenchymal abnormality after 2-4 weeks. Focal honeycombing was the major parenchymal abnormality after 4 weeks. High-resolution CT of the lung 9 months after paraquat exposure revealed localized fibrosis containing small cysts. Our study shows that the pulmonary manifestations of paraquat poisoning begin with air-space consolidation, which then leads to end-stage lung.