Aim: Cell‐free and concentrated ascites reinfusion therapy (CART) is useful for treating malignant ascites. We have previously experienced cases with no DVT‐PE despite a marked elevation in D‐dimer post‐CART. In this study, we assessed the changes in the D‐dimer levels in patients who received CART and investigated the association between elevated D‐dimer levels and occurrence of DVT‐PE. Methods: We performed an observational retrospective analysis of patients with gynecological malignancies treated with CART between March 2018 and April 2021. The selected patients had their D‐dimer levels measured before and post‐CART. The presence or absence of clinical DVT‐PE findings was then examined, and contrast‐enhanced computed tomography was performed using a DVT protocol in some cases. Results: Eleven patients received 17 CART procedures in this study. Patients of 16 procedures (94.1%) showed a significant elevation in D‐dimer levels on day 1 post‐CART. Changes in D‐dimer levels were monitored in these patients of 16 procedures. In all 16 cases, the D‐dimer levels decreased after day 2 post‐CART. Only one patient, who presented with respiratory failure, out of the patients of 16 procedures (6.2%) with elevated D‐dimer levels on day 1 had PE. Conclusions: D‐dimer elevation after CART is likely to be transient and a false‐positive. None of the patients in this study had PE if they were asymptomatic after CART, there is no need to strongly suspect PE only by D‐dimer elevation. In conclusion, D‐dimer measurement immediately post‐CART is not helpful in predicting the diagnosis of DVT‐PE. [ABSTRACT FROM AUTHOR]