Objective CD4 +IL-17 +cells are a group of newly discovered effector CD4 +T cells, which may play a key role in the pathogenesis of cancer.This study aims to investigate the expres-sion of CD4 +IL-17 +cells in pancreatic cancer and its correlation with the clinicopathological characteristics and prognosis of the dis-ease as well as the clinical significance of the cells in the microenvironment of pancreatic cancer. Methods We collected tumor tis-sue and tumor-adjacent normal tissue samples from 51 pancreatic cancer patients.We determined the expressions of CD34 and vascular endothelial growth factor ( VEGF) and measured the proportion of IL-17 +cells in the cancer tissue using immunohistochemistry and the fluorescence activated cell sorter, respectively, followed by analysis of their correlation with tumor angiogenesis, clinicopathological pa-rameters, and survival time of the patients. Results The percentage of CD4 +IL-17 +cells in tumor tissue was positively correlated with microvessel density (r =0.534, P<0.05) and the expression of VEGF in the tumor tissue (r=0.356, P<0.05).IL-17 +cells were expressed more highly in the tumorous than in the tumor-adjacent normal tissue (P<0.05), and the expression level was correla-ted with the stage of tumor, node, and metastasis (TNM) and lymph node metastasis (P<0.05), but not with the patients′gender or age, tumor size, tumor location, histological grade, or local invasion (P>0.05).Fifty (98.0%) of the patients were successfully followed up for 2-67 months, which revealed a median survival time of 16.6 ±4.8 months, significantly longer in those with a higher expression of intratumoral IL-17 +cells (P<0.05).Univariate analysis showed an association of the survival rate with the tumor size, TNM stage, lymph node metastasis, and level of intratumoral IL-17 +cells, while multivariate analysis showed the TNM stage to be an independent prognostic factor for the survival of the pancreatic cancer patients. Conclusion The expression of CD4 +IL-17 +cells in the tumor tissue is positively correlated with tumor angiogenesis, while that of IL-17 +cells with the clinicopathological parameters and survival time of the patients and therefore may serve as an important immune indicator for the prognosis of pancreatic cancer.