To ascertain whether tranexamic acid reduces the blood loss and transfusion rate and volumes; increase the prevalence of deep vein thrombosis (DVT); and investigate factors associated with DVT in patients undergoing primary bilateral total knee arthroplasties (TKAs) without use of chemical thromboprophylaxis. There were 874 patients (1748 knees) in the control group who did not receive tranexamic acid and 871 patients (1742 knees) in the study group who received tranexamic acid. Mechanical compression device was applied without any chemical thromboprophylaxis. Transfusion rates and volumes were recorded. DVT was diagnosed using both sonogram and venogram at 7 or 8 day post-operatively. Intra- and post-operative blood loss and transfusion volumes were significantly lower in the tranexamic acid group. The prevalence of DVT was 14% (245 of 1748 knees) in the control group and 18% (314 of 1742 knees) in the tranexamic acid group. Pre- and post-operative perfusion lung scans revealed no evidence of PE in any patients in either group. Coagulation or thrombophilic data or molecular genetic testing was not significantly different between the two groups. The use of tranexamic acid reduces the volume of blood transfusion and does not increase the prevalence of DVT or PE in the patients who did not receive routine chemical thromboprophylaxis after primary bilateral simultaneous sequential TKAs in Asian patients.