Objective: For 20 years, thromboprophylactic strategies (TSs) have been used after total hip replacement (THR). Our objective was to conduct a comprehensive cost effectiveness analysis (CEA) of TSs for THR from the health payer perspective. Methods: We extracted national data for Veteran patients receiving THR, including 1-year follow-up of all heath care utilization and complications of venous thromboembolic events (VTE: deep vein thrombosis, pulmonary embolism), thombocytopenia, bleeding, and death. Diagnostic codes were used to identify most complications. A comparative CE model, incorporating fondaparinux, was developed. Incremental cost-effectiveness ratios (ICERs) were calculated to compare TSs. Life-years gained (LYG) were calculated using actuarial tables for life expectancy. Since fondaparinux was rarely used in the VA, we applied rates from published trials and used our data to estimate proportional increases in complication rates for fondaparinux from day 50 through one year. We applied VA costs. Fondaparinux costs were based upon mean costs of outcomes of the other TSs. One-way sensitivity analyses (SA) were performed by incorporating the mean probabilities of DVT in the other TSs into the least-costly TS or decreasing the costs of complication arms by one standard deviation in all but the least-costly TS. Results: There were 1722 patients, 90 VTEs, and 48 deaths. Dalteparin was dominant; the least-costly per patient with fewest VTEs ($18,850, 2.4%) compared to warfarin ($18,953, 6.4%), enoxaparin ($19,965, 2.7%), enoxaparin/warfarin ($24,809, 21.6%), and fondaparinux ($20,759, 5.2%). Thus, ICERS indicated more costs and more events with other TSs. Deaths occurred in 2.4% of dalteparin patients versus 2.3% for enoxaparin and, estimated, 1.0%, for fondaparinux, thus ICERS for LYG were $35,754/LYG and $6,381/LYG, respectively. Dalteparin and other treatments were dominant over warfarin (2.9% deaths) and enoxaparin/warfarin (6.0% deaths)for LYG. Each SA showed dalteparin remained the least-costly TS per VTE avoided. Conclusion: Dalteparin was slightly more effective and less costly.