Aurora Healthcare, an integrated healthcare delivery system, wanted to use interhospital collaboration to improve quality. An opportunity for improvement at five Aurora hospitals was identified: Only 71% of patients received timely preoperative antibiotic prophylaxis. A Users Group approach was proposed to foster collaboration among the hospitals in a quality improvement (QI) effort. Although these hospitals differed in size, volume of cases, medical staffs, and antibiotic-delivery processes, they had common objectives and, many times, common barriers to the timely delivery of antibiotics. A Users Group approach to this QI initiative resulted in an 18% improvement in the number of patients who received timely administration of preoperative antibiotic prophylaxis (p < 0.001). This article describes the Users Group approach to QI at Aurora Healthcare in southeastern Wisconsin.