OBJECTIVES: To identify risk factors for deep vein thrombosis (DVT) in older patients with restricted mobility or functional disability. DESIGN: Cross-sectional. SETTING: Forty-two postacute care departments in France. PARTICIPANTS: Eight hundred twelve patients aged 65 and older. MEASUREMENTS: Twenty-two predefined characteristics were investigated, including medical and surgical risk factors, dependence in six basic activities of daily living (ADLs) rated using the Katz index, mobility, the reported value of the Timed Up and Go Test, and pressure ulcers. All patients underwent lower limb ultrasonography on the day of the cross-sectional study. RESULTS: DVT was found in 113 patients (14%, 33 proximal DVTs (4%) and 80 isolated distal DVTs (10%)). A positive trend was found in the odds of DVT for higher values on the Timed Up and Go Test for patients who were not bedridden or confined to a chair (P=.007). In two-level multivariable analysis adjusting for prophylaxis against venous thromboembolism, independent risk factors for DVT were aged 80 and older (adjusted odds ratio (aOR)=1.71, 95% confidence interval (CI)=1.05-2.79), previous history of venous thromboembolism (aOR=2.03, 95% CI=1.06-3.87), regional or metastatic-stage cancer (aOR=2.71, 95% CI=1.27-5.78), dependence in more than three ADLs (aOR=2.18, 95% CI=1.38-3.45), and pressure ulcers (aOR=1.85, 95% CI=1.05-3.24). CONCLUSION: Severe dependence in basic ADLs and higher Timed Up and Go Test score are associated with greater odds of DVT in older patients in postacute care facilities in France.