question: OBJECTIVE: Early reports suggest that patients with COVID-19 infection carry a significant risk of altered coagulation with an increased risk for venous thromboembolic events. This report investigates the relationship of significant COVID-19 infection and deep venous thrombosis (DVT) as reflected in the patient clinical/laboratory characteristics. METHODS: We reviewed demographics, clinical presentation, laboratory/radiological evaluations, Results of venous duplex imaging and mortality of COVID-19 positive patients (18-89 years) admitted to the Indiana University Academic Health Center. Using oxygen saturation, radiological findings and need for advanced respiratory therapies; patients were classified into mild, moderate or severe categories of COVID-19 infection. Descriptive analysis was performed using univariate and bivariate Fisher’s exact and Wilcoxon rank-sum tests to examine the distribution of patient characteristics and compare the DVT outcomes. A multivariable logistic regression model was used to estimate the Adjusted Odds Ratio of experiencing DVT while a Receiver Operating Curve (ROC)analysis to identify the optimal cutoff for d-dimer to predict DVT in this COVID-19 cohort. Time to the diagnosis of DVT from admission was analyzed using log-rank test and Kaplan Meier plots. RESULTS: Our study included 71 unique COVID-19 positive patients (mean age 61 years) categorized as having 3% mild, 14% moderate and 83% severe infection and evaluated with 107 venous duplex studies. DVT was identified in 47.8% of patients (37% examinations) at an average of 5.9 days post admission. Patients with DVT were predominantly male (67%, p =0.032) with proximal venous involvement. (29% upper and 39% in the lower extremities with 55% of the latter demonstrating bilateral involvement). Patients with DVT had a significantly higher mean d-dimer of 5447 ng/ml (SD 7032, p=0.0101), and Alkaline Phosphatase (Alk Po4) of 110 IU/L (p=0.0095) than those without DVT. On multivariable analysis, elevated d-dimer (p=0.038) & Alk Po4 (p=0.021) were associated with risk for DVT while age, gender, elevated CRP and ferritin levels were not. ROC analysis suggests an optimal d-dimer value of 2450 ng/ml cutoff with 70% sensitivity, 59.5% specificity, and 61% positive and 68.8% negative predictive values. CONCLUSION: This study suggests that males with severe COVID-19 infection requiring hospitalization are at highest risk for developing DVT. Elevated d-dimers, Alk Po4 along with our multivariable model can alert the clinician to the increased risk of DVT requiring early evaluation and aggressive treatment