Since its introduction in the 1970s, outpatient parenteral antimicrobial therapy (OPAT) has become a standard modality for patients with many infections requiring long-term intravenous antibiotic therapy. Delivery of OPAT may occur in physicians' offices, hospital clinics, specialized infusion centers, and currently most often, patient's homes, often self-administered. Patients are selected for OPAT by physicians familiar with both the course of their infections, their personal suitability for outpatient care, and the availability of reimbursement. OPAT is reportedly safe, effective, practical, and cost-effective. An OPAT Outcomes Registry contains information from >11,000 antibiotic courses administered from 1997 through 2000. Although a number of studies are purported to analyze the economic impact of OPAT on health care, a comprehensive, clinical outcomes-based pharmacoeconomic analysis, as described here, has, to our knowledge, yet to be done.