BACKGROUND: The aim of the present analysis from the epidemiologic international day for the evaluation of patients at risk for venous thromboembolism (VTE) in the acute hospital care setting (ENDORSE) study was to evaluate the prevalence of VTE risk in acute care hospitals and the proportion of at-risk medical and surgical patients who receive recommended prophylaxis in Switzerland. METHODS: All patients (age ≥ 40 years) admitted to a medical ward or those (age ≥ 18 years) admitted to a surgical ward in ten randomly selected Swiss hospitals were assessed for risk of VTE. The 2004 American College of Chest Physicians (ACCP) evidence-based consensus guidelines were used to assess VTE risk and to determine whether patients were receiving recommended thromboprophylaxis. RESULTS: 2000 patients were eligible; of these 1153 (58%) were in surgical wards, and 847 (42%) in medical wards. According to the ACCP criteria, the proportion of surgical patients at VTE risk was similar in Switzerland (68%, between hospital range 48-86%) in comparison to the global ENDORSE study (64%) (p = 0.296). The rate of at-risk medical patients was lower in Switzerland (21%, range 3-44%) than in the global study (42%) (p <0.001). The proportion of at-risk surgical patients with ACCP-recommended VTE prophylaxis was higher in Switzerland (81%, between-hospital range 76-93%) than in the global study (59%) (p <0.001). Among medical patients at risk, the use of recommended thromboprophylaxis was higher in Switzerland (61%, between-hospital range 0-84%) than in the global ENDORSE (40%) (p <0.001). However 56% of the patients with cancer, 41% with major trauma, and 29% undergoing vascular surgery did not receive any recommended prophylaxis. Among surgical patients at risk, the use of ACCP-recommended prophylaxis was lower in academic (77%) vs. non-academic (86%) institutions (p = 0.0025). CONCLUSIONS: In Switzerland, although the rate of recommended thromboprophylaxis is higher than in many countries, it is still improvable in medical patients at risk according to the ACCP guidelines. Consequently, hospital wide strategies for systematic risk factor assessment and implementation of practical tools to ensure appropriate use of prophylaxis in patients at VTE risk are required.