Catheter ablation for ventricular tachycardia (VT) is associated with perioperative thromboembolic risk. However, the strategy for postprocedural management remains unknown. The aim of this study was to evaluate the prothrombotic response after VT ablation in various coagulation biomarkers in patients with and without the administration of oral anticoagulation (OAC). Data from 112 patients (58 with uninterrupted OAC and 54 without) with structural heart disease who underwent endocardial VT ablation were retrospectively analyzed. We also included 41 patients who underwent ablation for premature ventricular contraction from the right ventricle and 13 patients who underwent electrophysiology study (the control group). Blood samples of coagulation markers were collected before and 3days after the procedure in all patients. The percentage of D-dimer levels≤1.0μg/mL at baseline was lower in the VT ablation groups (76% and 50% in the OAC and non-OAC groups, respectively) than in the other groups (100%). After 3days, the percentage remained at 67% in the OAC group; however, the non-OAC VT group demonstrated a remarkable decrease of 20%. Similarly, fibrin monomer complex, thrombin antithrombin, and prothrombin fragment 1+2 levels were well suppressed in the control, premature ventricular contraction, and OAC groups. However, the non-OAC group demonstrated increased coagulation markers both before and after 3days. Multivariate analysis demonstrated that OAC administration and normal coagulation markers at baseline were independent predictors of stable coagulation status after ablation. The coagulation cascade was significantly activated in patients undergoing VT ablation. Uninterrupted OAC administration suppressed the coagulation response, which might be associated with a reduction in perioperative prothrombotic risk.