['To examine whether the elevated preoperative plasma D-dimer levels show correlation with chemoresistance and poor prognosis in serous ovarian cancer patients.', 'Preoperative plasma D-dimer levels were measured in 125 patients with primary serous ovarian cancer (SOC).The correlations of plasma D-dimer levels with clinicopathological features, chemotherapeutic response, and survival outcome were further analyzed. Kaplan-Meier estimates were used to compute the survival functions and were compared using log-rank tests. Cox proportional-hazard regression analysis was used to evaluate the effects of D-dimer on progression-free survival (PFS) and overall survival (OS), controlling for potential confounding factors.', 'The median follow-up period was 49 (range 5-85) months. Elevated plasma D-dimer levels were positively associated with advanced FIGO stage (P = 0.010), residual tumor size (P = 0.017), the presence of malignant ascites (P = 0.028), increased serum CA125 level (P = 0.014), and neo-adjuvant chemotherapy (P = 0.008). The patients with elevated plasma D-dimer levels had significantly higher chemoresistance rates (56.41 %) compared to the normal plasma D-dimer levels (20.93 %). Additionally, it was found by the univariate analysis that elevated plasma D-dimer levels were closely related with a low 5-year PFS rate (28.21 vs 52.33 %, P = 0.002) and a poor 5-year OS (30.77 vs 63.95 %, P < 0.001). However, after adjustment for other factors, high plasma D-dimer levels were only closely correlated with a poor 5-year OS (HR 1.901, 95 % CI 1.021-3.540; P = 0.043).'] Is elevated preoperative plasma D-dimer level a useful predictor of chemoresistance and poor disease outcome for serous ovarian cancer patients?