Abstract: Objective To test the validity of Caprini risk assessment scale in identifying hospitalized critically ill patients with high venous thromboembolism (VTE) risks. Methods A case-control study was conducted, with 78 VTE patients who were admitted to the ICU of Sichuan Provincial People’s Hospital from February 2008 to June 2014 in the case group, and a randomly selected group of 156 non-VTE patients who were admitted during the same period serving as controls. The medical history, laboratory tests and other related clinical data of the participants were retrieved. Their VTE risks were assessed using the Caprini risk assessment scale. Multivariate logistic regression analysis was performed to establish the association between Caprini VTE risk classification and the presence of VTE. Results VTE patients had a Caprini score of 8.7±3.5, higher than that of the controls (4.2±2.6). More than 88.4% of VTE ill patients were rated as having “high or very high” risk of VTE by Caprini rating scale, significantly higher than the percentage in the controls ( P<0.001). The logistic regression model identified eight risk factors in the Caprini scale as predictors of VTE: bed-bound in internal medicine wards, severe lung disease (<1 month), sepsis (<1 month), large operation (<1 month), malignant tumor (past or prevalence), deep venous thrombosis (DVT)/pulmonary thromboembolism (PTE) history, family history, and thrombosis of multiple trauma (<1 month). The odds ratio of VTE in patients with a high and very high risk as identified by Caprini scale was 2.042 and 11.681, respectively, compared with those with a low risk. Conclusion Caprini risk assessment scale can predict the risk of VTE in hospitalized critically ill patients.