Class of 2017 Abstract / Objectives: The objective of this retrospective cohort chart review was to evaluate the safety and efficacy of extended infusion beta-lactam regimens as part of treatment of acute CF pulmonary exacerbations in adults and pediatric patients. Methods: Inclusion criteria: adult and pediatric patients (age 1 month or older) with CF diagnosis who were admitted to BUMC-T for acute pulmonary CF exacerbation, and who received meropenem, imipenem, aztreonam, piperacillin-tazobactam, and or cefepime during their hospitalization (between 1/1/2011 and 10/30/2015). Exclusion criteria: pregnant women and admissions less than 24 hours. The two groups evaluated were patients receiving treatment (group 1) prior to extend infusion practices (Jan 2011 – Dec 2012) and (group 2) after implementation of extend infusion practices (Jan 2013 – Oct 2015). Data was collected from medical records using both the Sunrise Clinical Manager and EPIC electronic medical record systems. The data was then analyzed for differences in efficacy outcomes (e.g., length of hospitalization, lung function, return to baseline lung function), changes in renal and hepatic function, incidence of documented adverse drug effects, and potential factors associated with increased risk for changes in renal or hepatic function with use of extended infusion beta‐lactam regimens. Results: Pending. Efficacy outcomes: - length of hospitalization - improvement in lung function - return to baseline lung function Safety outcomes: - changes in renal and hepatic function - incidence of documented adverse drug effects - potential factors associated with increased risk for changes in renal or hepatic function Conclusions: Pending. As this study is being conducted at one academic medical center, conclusions may not be generalizable to other institutions.