Objective This research is aimed to investigate the efficacy and toxicity of icotinib for lung adenocarcinoma pa-tients with poor performance status and unknown EGFR gene status .Methods A total of 27 lung adenocarcinom patients with poor Eastern Cooperative Oncology Group-Performance status(ECOG-PS) and unknown EGFR gene status referred to Chongqing Canc-er Institute from August 2012 to August 2014 were analyzed .Icotinib (125 mg) was orally administered three times per day .Asess the efficacy and adverse reaction ,calculate survival rates .Results Among the 27 patients ,the objective response rate(ORR) and disease control rates(DCR) were 29 .6% and 81 .5% ,respectively .The median progression free survival time was 6 .0 months .A to-tal of 70 .4% of patients had an significant improvment in ECOG-PS scores ,following icotinib treatment (Z= - 2 .157 ,P= 0 .031) . Fatigue ,anorexia and diarrhea were the most frequent adverse reaction ,which defined as grade 1 to 2 rashes .Conclusion Lung ade-nocarcinoma patients with poor performance status and unknown EGFR gene status may benefit from icotinib therapy ,and patients were tolerated well .