BACKGROUND: Venous thromboembolism is an important patient safety issue. The authors sought to compare the predictive capacity of the 2005 and 2010 Caprini Risk Assessment Models for perioperative venous thromboembolism risk. METHODS: The authors performed a retrospective, observational, crossover study using an established surgical outcomes database. A total of 3334 adult plastic surgery patients were identified. Patients were risk-stratified using both the 2005 and 2010 Caprini Risk Assessment Models. Each patient served as his or her own control, resulting in precise matching for identified and unidentified confounders. The outcome of interest was 60-day, symptomatic venous thromboembolism. The predictive capacities of the 2005 and 2010 Caprini risk scores were compared. RESULTS: Use of the 2010 Caprini Risk Assessment Model resulted in a systematic increase in the aggregate risk score. The median 2010 Caprini score was significantly higher than the median 2005 Caprini score (6 versus 5, p<0.001). When compared with the 2010 model, the 2005 Caprini Risk Assessment Model was able to better separate the lowest and highest risk patients from one another. Patients classified as "super-high" risk (Caprini score>8) using the 2005 Caprini Risk Assessment Model were significantly more likely to have a 60-day venous thromboembolism event when compared with patients classified as super-high risk using the 2010 guidelines (5.85 percent versus 2.52 percent, p=0.021). CONCLUSIONS: When compared with the 2010 Caprini Risk Assessment Model, the 2005 Caprini Risk Assessment Model provides superior risk stratification. The 2005 Caprini Risk Assessment Model is the more appropriate method to risk-stratify plastic surgery patients for perioperative venous thromboembolism risk. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.