e18273 Background: Pegfilgrastim is used in patients at significant risk for febrile neutropenia following myelosuppresive chemotherapy. Labeling for pegfilgrastim requires administration the day after administration of chemotherapy. The pegfilgrastim on-body injector allows for delivery at home, without having to return to the clinic. Rates of appropriate delivery of pegfilgrastim via the on-body injector have not been studied in large scale outside of controlled environments. This retrospective review investigates the rate of appropriate delivery of pegfilgrastim via the on-body injector in a large heath system. Methods: Reports were created listing monthly clinic administration of the pegfilgrastim on-body injector at nineteen outpatient cancer care clinics from July 1st, 2016 to December 31st, 2016. Patient charts were reviewed for reported non-delivery of the medication. Results: Three hundred eighty-nine injections from 149 patient charts were reviewed. Of these injections, eight were not delivered (non-delivered rate = 2.1%). Four other administrations resulted in only partial dose delivery or unknown if dose was delivered (partial/unknown rate = 1%), leading to a failure rate of 3.1 with an appropriate delivery rate of 96.9%. Conclusions: In one health system’s experience, 96.9% of pegfilgrastim on-body injector administrations were delivered as planned. A process for real time evaluation of delivery rates should be created to address the 3-4% non-delivered dosing.