Purpose.　This　study　examined　the　tumor　expression　of　programmed　cell　death　ligand　1　(PD-L1)/programmed　cell　death　protein　1　(PD-1)　in　patients　with　GEP-NEN.　This　study　aims　to　reveal　the　relationship　of　their　expression　with　clinicopathological　characteristics　and　prognosis.　Methods.　PDI　and　PD-L1　expression　in　tumors　from　120　GEP-MEN　patients　was　evaluated　using　immunohistochemistry.　The　correlations　of　the　expression　of　PDL1/PD1　and　clinicopathological　features　were　assessed.　Results.　Immunohistochemical　staining　indicated　that　PD-L1　was　expressed　in　the　tumor　cells　of　52.5%　patients　with　GEP-NENs,　and　PD-L1　expression　was　positively　correlated　with　the　World　Health　Organization　(WHO)　classification,　American　Joint　Committee　on　Cancer　(AJCC)　stage,　lymphatic　metastasis　and　prognosis.　Meanwhile,　PD-1　was　expressed　in　tumor　infiltrating　lymphocytes　within　55.8%　tumor　samples,　and　PD-1　expression　was　positively　correlated　with　AJCC　stage　and　GEP-NENs　prognosis.　Moreover,　survival　analysis　indicated　that　the　overall　median　survival　of　patients　with　PD-L1/PD-1-positive　tumors　significantly　differed　from　that　of　patients　with　PD-L1/PD-1-negative　tumors.　Multivariate　analysis　confirmed　that　AJCC　stage　and　Chromogranin　A　expression　in　tumor　tissues　were　independent　prognostic　factors　for　overall　survival.　In　conclusion,　PDL1　was　an　independent　prognostic　factor　for　patients　with　GEP-NENs.　Our　results　suggested　that　patients　with　GEP-NENs　might　be　appropriate　for　PD1/PDL1-targeted　therapy.　Conclusions.　Our　findings　show　that　the　expression　of　PD-L1　and　PD-1　correlates　with　patient　prognosis,　and　may　thus　serve　as　potential　pathological　prognostic　markers　of　GEP-NENs.　Immunotherapy　using　PD-1/PD-L1　inhibitors　may　be　a　promising　strategy　for　GEP-NENs　patients　with　PD-L1/PD-1　positively　expressed.