OBJECTIVES describe the prevalence of venous thromboembolism (VTE), pulmonary embolism (PE) and deep vein thrombosis (DVT) without PE among all hospitalized patients and the percentages of those occurring during the hospital stays. METHODS Statistics are issued from the national PMSI MCO databases which are encoded using the CIM10. The codes used for VTE are I801 to I809 for DVT and codes I260, I269 for PE... Any stay with a the ICD-10 codes selected regardless of the Principal Diagnosis of Medical Unit Summaries and whatever its position (Principal, Related or Associated Diagnosis) was considered as a hospital-occurred  thrombosis unless it was the Principal Diagnosis of the first Medical Unit Summary of the stay. To eliminate outpatient consultations or in day care, stays of < 48 hours were excluded. The term of hospital-occurred is preferred to hospital-acquired VTE suggesting a nosocomial origin which can be the case or not. RESULTS The results bear on the 18 683 603 hospital stays in 2010-2011. Out of 100 hospital stays involving VTE, for 40.3% VTE was the cause of hospitalization whereas 59.7% can be considered to have occurred during hospital-stay. These distributions are of 25.6% and 74.4% for DVT respectively 53.8% and 46.2% for PE. The age of patients varies little with whether VTE, DVT, and PE were hospital-occurred or not and are similar in men and women. The percentage of mortalities of these  VTE is high and reaches 6.58% and the mortality from VTE, DVT, and PE is multiplied by a factor of 3 to 4 (p<.0001) when hospital-occurred. CONCLUSIONS The high proportion of hospital-occurred VTE is an alarming situation that should question the quality of prevention and/or its effectiveness. VTE prevention policies must be strengthened in hospitals for the sake of patients and healthcare savings alike.