A 75-year-old male was diagnosed with central squamous cell carcinoma of the left lung, who has been given 3-dimensional conformal radiotherapy of total dose with 60 Gy in 30 fractions. Three years later, the tumor relapsed in situ and he received another stereotactic radiotherapy with a total dose of 40 Gy at a margin of planning target volume (PTV) in 10 (5 fractions/week) at 4 Gy/fraction. Gefitinib (250 mg/day) was initiated immediately after radiotherapy. Obstructive atelectasis in the left lung and increased pleural effusion occurred at the fourth month after radiotherapy. As this patient has been detected with deletion in exon 19 of the EGFR gene, gefitinib was continuous administered without interruption. After another 4 months, the atelectasis in the left lung reexpanded significantly. To the best of our knowledge, this is the first report in the literature that EGFR tyrosine kinase inhibitors (EGFR-TKI) reversed the radiation atelectasis of pulmonary in the nonsmall cell lung cancer (NSCLC) patient.