Objective To evaluate the effectiveness and safety of gefitinib retreatment beyond progression(GRBP)in non-small cell lung cancer(NSCLC)patients with rare EGFR mutations.Methods We retrospectively analyzed six rare-EGFR-mutation NSCLC patients from Jan 2011 to Dec 2015.Those patients had previous disease control and then disease progression according to Response Evaluation Criteria in Solid Tumors version 1.1(RECIST v1.1)after taking oral gefitinib 250 mg once a day.After that,continuing gefitinib was decided by clinicians′ experience at the same treatment option.The primary endpoints were response rate(RR),overall survival(OS),the first and second progression-free survival(PFS-1 and PFS-2).Safety was assessed according to the NCI-CTCAE version 4.0.Results After initial treatment of gefitinib,4 patients achieved partial response(PR)and 2 patients showed stable disease(SD),with RR being 66.7％.The median PFS-1 and PFS-2 were 10 months(95％CI 6.6-13.4)and 9 months(95％CI 6.9-11.1),respectively.The median OS time was 28 months(95％CI 10.4-45.6).The most common treatment-related adverse events were fatigue,diarrhea,rash,itching and elevated transaminases.Conclusion In our study,gefitinib retreatment beyond disease progression is effective with a manageable tolerability profile.