Background: Needleless intravenous devices have now been implemented by many institutions worldwide. A rationale for their use has been a reduction in the number of needlestick injuries. Objective: The aim of this review is to outline the possible benefits and dangers of needleless intravenous systems. Review: Many early reports demonstrate a reduction in needlestick injuries after the implementation of a needleless intravenous device; however, not all such reductions are directly attributable to the device itself. Furthermore, good evidence suggests that needlestick accidents prevented by needleless intravenous devices pose little threat to health care workers. Finally, increasing reports associate bacteremias with the use of needleless intravenous devices. Early reports described devices used in the home care setting; however, recent reports are from acute health care settings, including intensive care units. Conclusion: Ongoing critical review of the benefits, risks, and costs of needleless intravenous devices is required. (AJIC Am J Infect Control 1999;27:431-4)