Background: Anticoagulation of the blood circuit with heparin is essential for hemodialysis, but exposes patients to several risks (bleeding, thrombocytopenia, etc.). The use of citric acid-based dialysate (CitA-D) allows the reduction of heparin in conventional hemodialysis. We evaluated the feasibility of using CitA-D in postdilution online hemodiafiltration (OL-HDF) and of removing heparin. Methods: We prospectively compared chlorhydric acid-based dialysate with CitA-D in 10 patients treated by OL-HDF. First, we reduced heparin by half the dose and then we totally removed anticoagulation. Results: For all 120 sessions using heparin-free CitA-D, only one clotting episode related to an arteriovenous fistula stenosis was observed. No adverse clinical effect was observed. (Kt/V)<sub>sp</sub>, predialytic serum bicarbonate, calcium, phosphate, parathroid hormone, and β<sub>2</sub>-microglobulin remained the same in all cases. Conclusion: Our data suggest that the use of CitA-D in OL-HDF is safe and allows heparin removal in most patients.