Hemorrhagic cystitis is a major potential toxicity of ifosfamide that can be prevented by administering mesna along with the cytotoxic agent. Mesna is generally administered by the intravenous route, although experience with oral delivery of the drug has increased. The continuous subcutaneous administration of mesna has the advantage of not requiring intravenous access. In addition, subcutaneous delivery of the neutralizing agent will not be associated with the risk of inadequate urinary mesna concentrations, such as in a patient taking oral mesna who experiences severe ifosfamide-induced emesis and is unable to absorb the drug. Limited clinical experience with continuous subcutaneous mesna administration suggests it is a safe, practical, and economic method of drug delivery that permits ifosfamide to be administered successfully in the outpatient setting.