OBJECTIVES: To assess adherence with therapeutic guidelines in the treatment of venous thromboembolism and pulmonary embolism in clinical practice. METHODS: An observational retrospective analysis on six Local Health Units’ administrative and laboratory test databases was conducted, with around 2.7 Million beneficiaries involved. Patients discharged alive from a hospitalization with a diagnosis of venous thromboembolism and pulmonary embolism between January 1st, 2010 and December 31st, 2012 were included. Since the index date (date of discharge), patients were characterised and followed-up basing on previous and following 12 months, respectively. RESULTS: A total of 4,499 patients were included in the analysis. More prevalent therapeutic patterns and sequences occurred as follows. Among included patients, considering all the follow-up period, 33% had heparin only (average duration of heparin treatment equal to 143 days), 26% had vitamin K antagonist (VKA) only, 4% had fondaparinux only, and 12% had none of the previous treatments. Eight percent of included patients were initially prescribed for VKA and combined heparin during the follow-up period (average duration of heparin treatment equal to 76 days), 4% were initially prescribed for heparin (average duration of heparin treatment equal to 150 days) and combined VKA during the follow-up period. Four percent of included patients were initially prescribed for VKA and switched to heparin during the follow-up period  (average duration of heparin treatment equal to 99 days) while 3% were initially prescribed for heparin (average duration of heparin treatment equal to 75 days) and switched to VKA during the follow-up period. CONCLUSIONS: Adherence with therapeutic guidelines in the treatment of venous thromboembolism and pulmonary embolism in clinical practice appeared unsatisfactory since a high percentage of patients are treated with heparins for time period longer than recommended instead of switching to VKAs.