UNLABELLED: BACKGROUND: Residual vein obstruction (RVO) detected on compression ultrasonography of the leg after a few months of anticoagulation therapy might be able to identify patients with deep vein thrombosis (DVT) at high risk of having a recurrent venous thromboembolism (VTE). Aim: To determine whether RVO is associated with an increased risk of recurrent events in patients with DVT. PATIENTS AND METHODS: A systematic literature search strategy was conducted using MEDLINE, EMBASE, and the Cochrane Register of Controlled Trials. We selected 14 articles (nine prospective cohort studies and five randomized controlled trials) that included patients with DVT who had an assessment for RVO with the use of compression ultrasonography. Two reviewers independently extracted data onto standardized forms. RESULTS: Overall, the presence of RVO was not associated with an increased risk of recurrent VTE (odds ratio [OR] 1.24, 95% confidence interval [CI] 0.9-1.7) in patients with unprovoked DVT who stopped oral anticoagulation therapy at the time of RVO assessment. However, RVO was significantly associated with recurrent VTE in patients with any (unprovoked or provoked) DVT (OR 1.5, 95% CI 1.1-2.0). CONCLUSIONS: RVO was associated with a modestly increased risk of recurrent VTE in patients with DVT (unprovoked and provoked). However, RVO did not seem to be a predictor of recurrent VTE in patients with unprovoked DVT following anticoagulation discontinuation. Further prospective studies are needed to assess the role of RVO in patients with unprovoked DVT.