OBJECTIVES: There are limited data documenting common strategies used for inpatient thromboprophylaxis or describing the costs associated with common treatment modalities. The aim of the study was to assess treatment patterns, utilization of health care resources and hospital costs associated with thromboprophylaxis in real-world clinical practice in Poland. METHODS: Data from inpatient records were collected prospectively for patients hospitalized in 25 departments between 31.04.2004 and 31.05.2005. Stratified analyses were performed by baseline risk of thrombosis and means of total cost for each group were calculated, using participating hospitals account systems. Costs comparisons related to risk groups were performed using non-parametric tests with significance level of 0.05. RESULTS: The database contains information about 5348 patients. Of these 35% were general surgery, 23% medical, 15.3% vascular and 13% orthopedic surgery patients. 59% of patients were at highest risk of VTE (I), 24% at high (II), 10% at moderate (III) and 7% at low risk (IV). Thromboprophylaxis received 84%, 77%, 71% and 60% patients in I, II, III, and IV group, respectively. Most admissions (76,%) involved LMHHs treatments, administered for mean 10.2, 6.3, 6.0 and 5.8 days in group I,II,III and IV respectively. Adverse events related to thromboprophylaxis occured in 2% of patients; 85% of these were minor hemorrhages, 9% major hemorrhages, 2% thrombocytopenia. Post-discharge thromboprophylaxis was indicated for 34.6% patients, most frequently in patients after orthopedic surgery (81.3%), trauma (66.3%) or cardiological hospitalizations (49%). The most common regimen in extended thromboprophylaxis were LMWHs (77%). Mean cost of thromboprophylaxis was 999 (+/-5964) PLN in I, 327(+/-1598) PLN in II, 260(+/-695) PLN in III and 232(+/-842) PLN in group IV (1 EURO= 4 PLN, 2005) (p=0.0001). CONCLUSION: Results from this study indicate that inpatient thromboprophylaxis is in line with clinical guidelines. The risk stratification of hospitalized patients allows for the estimation of costs