OBJECTIVE. This study was designed to establish the rates of treatment failure for community-acquired pneumonia that are acceptable to knowledgeable and experienced physicians, in order to facilitate the interpretation of existing studies and the design of new studies aimed at optimizing the duration of antibiotic therapy. Reducing the duration of antibiotic therapy is one strategy for reducing antibiotic exposure and thereby minimizing the potential for the emergence of antimicrobial resistance. DESIGN. Survey soliciting the acceptable failure rate for treatment given to an adult patient with uncomplicated community-acquired pneumonia treated with standard-of-care therapy in the outpatient setting. Analysis was performed using a modification of established methods of contingent valuation analysis. PARTICIPANTS. Six hundred eighty infectious diseases physicians in North America who were also members of the Emerging Infections Network of the Infectious Diseases Society of America. RESULTS. Three hundred seventy-five (55.1%) of 680 physicians responded to the survey. The median acceptable failure rate for treatment was 13.5%. Five hundred ten respondents (75.0%) found a failure rate of 7.3% acceptable, and 170 respondents (25.0%) found a failure rate of 19.8% acceptable. CONCLUSIONS. This study identified the failure rates for treatment of community-acquired pneumonia that were acceptable to infectious disease physicians. This range of acceptable treatment failure rates may facilitate the design of studies aimed at optimizing the duration of antimicrobial therapy for community-acquired pneumonia.