Purpose: We evaluated the efficacy of continuous administration of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) in patients with end-stage non-small cell lung cancer. Method: Our study included 33 patients most recently treated with EGFR-TKI for non-small cell lung cancer that had once been responsive to EGFR-TKI but eventually showed worsening. We compared patients who discontinued EGFR-TKI within one month (n=16) after their disease progressed and those who continued the treatment (n=17). Results: The median survival time was significantly longer in patients who continued EGFR-TKI (191 days) than in those who discontinued the treatment (62 days) (p=0.0098). Adverse events experienced by patients who continued the treatment included Grade 1 eruption in six, Grade 2 eruption in one, Grade 1 diarrhea in one and Grade 1 AST/ALT elevation in four. All of these adverse events were manageable. Conclusion: In patients with non-small cell lung cancer initially responsive to EGFR-TKI but eventually showing worsening and becoming unfit for cytotoxic anticancer drugs, continuous administration of EGFR-TKI may extend their survival with acceptable toxicity. Further investigation of this strategy is warranted. Palliat Care Res 2011; 6(1): 119-125