OBJECTIVE Endovenous heat-induced thrombosis (EHIT) and deep venous thrombosis (DVT) are well-known complications after superficial endovenous thermoablation. We investigated the efficacy of rivaroxaban in preventing EHIT and DVT after endovenous laser ablation (EVLA). METHODS We retrospectively analyzed a consecutive series of patients presenting with truncal varicosis class C to C undergoing EVLA. After EVLA, all patients received oral rivaroxaban (10 mg) or subcutaneous fondaparinux (2.5 mg) once daily for 3 consecutive days. The primary end point was the composite of EHIT or DVT assessed by duplex ultrasound imaging after 1 and 4 weeks. EHIT class 1 was defined as the thrombus extending to the saphenofemoral junction. Extension into the deep venous system with a cross-sectional area obstruction <50% was considered EHIT class 2. EHIT class 3 was defined as >50% cross-sectional area obstruction. EHIT class 4 was total occlusion of the femoral vein. The secondary end points were minor or major bleeding, paresthesia, and skin burns. RESULTS Between February 2009 and December 2015, 391 patients (473 limbs) were treated with EVLA of the truncal saphenous vein. The primary end point occurred in 13 of 166 (7.8%) and 14 of 225 (6.2%) after 1 week and in 13 of 166 (7.8%) and 15 of 225 (6.7%) after 4 weeks comparing the rivaroxaban and fondaparinux groups (P = .659). EHIT class 1 was observed in 20 patients (5.1%) and EHIT class 2 in five (1.3%). No patients had EHIT class 3 or 4. The incidence of DVT was one of 166 (0.6%) in the rivaroxaban group and two of 225 (0.9%) in the fondaparinux group (P = .750). Minor bleeding events occurred in 17 of 166 patients (10.2%) and in 20 of 225 patients (8.9%), respectively (P = .652). No major bleeding events were observed. Paresthesia was observed in 12.5% in the rivaroxaban group and in 17.8% in the fondaparinux group. No skin burns were observed. CONCLUSIONS Rivaroxaban offers an oral medication approach showing no difference in preventing EHIT and DVT compared with fondaparinux, without increased bleeding risk.