In hospitalized patients, venous thromboembolism (VTE) is an important cause of morbidity and mortality. Despite evidence demonstrating efficacy and safety of pharmacological thromboprophylaxis in the prevention of VTE, its use remains low. The aim of this study is to compare the incidence of use of thromboprophylaxis before and after a pharmacy-led thrombosis prevention campaign in medical patients hospitalized in a community hospital. A pharmacy-led multifaceted thromboprophylaxis campaign including continuing education activities for physicians and pharmacists and individualized academic detailing activities supported by clinical tools were implemented over an 8-week period. In a quasi-experimental study, the incidence of pharmacological thromboprophylaxis was evaluated using a retrospective chart review and compared before and after the campaign in medical patients at high and non-high risk of VTE as defined by the American College of Chest Physicians criteria. The medical charts of 461 patients were reviewed; 66 and 58 patients were at high-risk of VTE prior to and after the campaign, respectively. After the campaign, thromboprophylaxis ordering in high-risk patients increased from 15.2 to 43.1% (adjusted OR: 6.8; 95% CI: 2.5-18.0). Thromboprophylaxis ordering in non-high risk patients was 1.8% before the campaign and 6.0% after. This increase was not statistically significant (adjusted OR: 4.6; 95% CI: 1.0-20.4). The incidence of pharmacologic thromboprophylaxis in hospitalized medical patients at high-risk of VTE increased significantly after the campaign but remained sub-optimal. Longer or a different campaign may be needed to ensure long-term optimal thromboprophylaxis use.