Administration of β-lactam antibiotics by extended infusion optimizes the pharmacodynamic properties and bactericidal activity of these agents resulting in a potential improvement in patient outcomes and reduction in drug expenditure. Consequently, a pharmacist-led piperacillin-tazobactam extended 4-hour infusion guideline was implemented hospital-wide at a 500-bed academic medical center. Each piperacillin-tazobactam infusion was prospectively monitored for 5 weeks to ensure accurate administration and identify barriers to guideline adherence. Overall, a total of 103 patients received 1215 doses of piperacillin-tazobactam by extended infusions. In all, 98% of the doses were administered at the correct extended infusion rate and 94% of the doses were given at the scheduled time. There were a total of 20 missed doses and 53 delayed doses, accounting for 2% and 4% of the total administered doses, respectively. The primary barrier to adherence was the patient not being on the unit at the time of the scheduled dose followed by the piperacillin-tazobactam dose not being available on the floor. While insufficient power prevented meaningful evaluation of clinical outcomes, we anticipate a conservative annual estimated cost savings of $108,529. Key elements contributing to our success included consistent pharmacy leadership, multidisciplinary involvement, thorough inservicing to health care professionals, hospital-wide implementation, and extensive quality assurance monitoring.