OBJECTIVES: The urgent global threats of the climate crisis and antimicrobial resistance have the potential to be addressed in part by increasing the use of outpatient antimicrobial therapy (OPAT). Our study aimed to appraise the environmental impact of three commonly used OPAT pathways, and the traditional inpatient model of IV antimicrobial therapy. METHODS: We assessed the CO RESULTS: We found that the administration of IV antibiotics in hospital is associated with a substantial environmental impact compared to OPAT. When OPAT is self-administered in the patient's home, we discovered a CO CONCLUSIONS: Our study demonstrates that using OPAT reduces the environmental impact of delivering antimicrobial therapy compared to inpatient treatment. As it is delivered away from the hospital setting, it may also reduce the risks to health associated with inpatient care. While we have shown that the reduction in CO