Objective: Venous thromboembolism (VTE), which comprises pulmonary embolism and deep vein thrombosis, is a known complication of total knee arthroplasty (TKA). However, data on the risk of VTE after simultaneous bilateral TKA, compared to that after single knee arthroplasty, is scarce. Methods: A retrospective study of electronic medical records of all adult patients who underwent simultaneous bilateral TKA or single unilateral TKA was conducted. Results: A total of 669 patients underwent TKA. Of these, 134 underwent simultaneous bilateral TKA while 535 underwent single unilateral TKA. All patients underwent pharmacological thromboprophylaxis for a median duration of 30 days. The incidence of confirmed VTE in all patients was 1.8% (95% confidence interval, CI: 0.9-3.0). VTE occurred in 8 of the 134 patients (6%, 95% CI: 2.2-10.4) who underwent simultaneous bilateral TKA and in 4 of the 535 patients (0.7%, 95% CI: 0.2-1.5) who underwent single unilateral TKA. The odds ratio of confirmed VTE was 8.42 (95% CI: 2.49-28.4; p=0.001). Conclusion: The risk of VTE is significantly higher following simultaneous bilateral TKA than following single unilateral TKA. Further studies are needed to evaluate high-risk patients and to determine the appropriate thromboprophylaxis regimen.