Abstract: Objective:To investigate the correlation of plasma D-dimer levels with the response to first-line chemotherapy and the prognosis of patients with serous ovarian cancer (SOC). Methods:The preoperative plasmic D-dimer levels of 143 patients with prima -ry SOC were retrospectively evaluated. The patients were admitted to Tianjin Medical University Cancer Institute and Hospital between January 2008and May 2010. The patients were divided into two groups on the basis of plasmic D-dimer levels. Group A consisted of 100 patients with a normal plasmic D-dimer level of ≤ 0.3 mg/L. Group B included 43patients with an increased plasmic D-dimer level of > 0.3 mg/L. The correlations of the different plasmic D-dimer levels with clinicopathological features, therapeutic effects, and surviv-al outcomes were further analyzed.Results:The plasmic D-dimer levels were positively correlated with the staging of the Federation of International Gynecology and Obstetrics, residual tumor size, presence of malignant ascites, preoperative serum CA125 level, and neo-adjuvant chemotherapy. Group B exhibited a significantly lower ( P<0.001) complete response (CR) rate of 34.88% (15/43) than group A, which yielded a CR rate of73.00% (73/100). The progression-free survival and overall survival rates of group B were significantly lower than those of group A ( 25.58% vs . 50.00% and32.56% vs . 65.00%;P<0.05). Multivariate analysis revealed that the plasmic D-di mer level is an independent prognostic factor associated with unfavorable prognosis.Conclusion:Increased preoperative plasmic D-di -mer levels may be a potential biomarker of weak responses to first-line chemotherapy and poor clinical outcomes in patients with SOC.