Subcutaneous injections account for an increasing share of total needle-stick injuries (NSI). OBJECTIVE: The objective was to document the possible cost savings related to the introduction of a protected needle (safety shaft) used to administer LMWH. METHODS: we estimated the frequency and the costs of NSI attributable to treatment with LMWH in a tertiary care hospital, and modeled a countrywide estimate. Risks : We collected data on yearly NSI due to recapping in a large tertiary care center and related this figure to the total number of needles used. We derived a risk of NSI per 100,000 needles used and multiplied it by the number of injections with LMWH per year in hospitals countrywide. Costs : we estimated the cost of a NSI from the resources used in the hospital to manage personnel after a NSI. The actual resources used were prospectively collected during the year 1997 and were compared to other observed data (hospital survey). >From these data we built a decision tree and compared the results to the recommended practice. Costs were estimated from the viewpoints of both hospital and society. Infection : the costs related to the risk of viral infection were not included. RESULTS: The rate of NSI due to recapping was 5.2 per 100,000 punctures, the total number of LMWH needles used in hospitals was 14,861,000.. The total societal cost of managing a NSI was assessed to be $1,919 assuming that all the recommended procedure were followed. From the hospital viewpoint, the cost became $1,174 . The large discrepancy between recommended and actual practice lead to significant reductions in costs. The potential savings linked to the use of the safety device were conservately estimated. CONCLUSION: Using safer devices for LMWH injections may result in cost savings by reducing the costs of NSI management.