ABSTRACT Purposes Hyperfibrinogenemia in various carcinomas has previously been described. But, in advanced gastric cancer, whether or not chemotherapy-induced changes in fibrinogen level relate to chemotherapeutic response and prognosis remains unclear. The purposes of this study were: 1) to analyze the correlation between the chemotherapy-induced changes of plasma fibrinogen level and the chemotherapeutic response after the first two courses of standard first-line chemotherapy; and 2) to evaluate the prognostic significance of the change of plasma fibrinogen level in patients with advanced gastric cancer. Methods In this retrospective study, the data of 84 patients with advanced gastric cancer were collected. After a median follow-up time of 280 days (range,58-1992days) 65patients had died by the cutoff day.The association between the pre-and post-chemotherapy fibrinogen levels and patient clinic characteristics, or the association between the changes in fibrinogen and the response to chemotherapy, were analyzed using SPSS software. Furthermore, the prognostic value of the change of fibrinogen levels was assessed. Results The median pre-chemotherapy plasma fibrinogen levels were 4.55g/L. Pre-chemotherapy plasma fibrinogen levels correlated significantly with the age(p = 0.017).There is a significant link between the decrease in fibrinogen level and partial response (PR; p = 0.000) and stable disease (SD; p = 0.015). But there is not similar decrease in progressive disease (PD; p = 0.851). If the decrease is more than10%, we get longer overall survival (OS; p = 0.03). Conclusions This study showed that the reduction in plasma fibrinogen levels induced by chemotherapy might be a promising biomarker for evaluating the efficacy of chemotherapy in advance gastric cancer. In addition, the change of plasma fibrinogen levels could be used as a prognostic parameter for the overall survival of patients with advanced gastric cancer. Relationship between the decrease fibrinogen level and chemotherapeutic response. group N pre-chemotherapy post-chemotherapy P value Total 84 4.55 ± 1.25 4.02 ± 1.38 0.001 DCR 72 4.45 ± 1.27 3.90 ± 1.14 0.000 PR 14 4.88 ± 1.29 3.37 ± 0.71 0.000 SD 58 4.41 ± 1.25 4.03 ± 1.19 0.015 PD 12 4.83 ± 1.18 4.72 ± 2.32 0.851 Disclosure All authors have declared no conflicts of interest.