BackgroundResidents in residential aged care facilities (RACFs) have a high number of medication-related problems. Integrating on-site pharmacists (OSPs) into this setting is a possible solution and is currently gaining traction in Australia and internationally. The Pharmacists in Residential Aged Care Facilities (PiRACF) cluster-randomised controlled trial integrated pharmacists into the RACF care team to improve medication management. The aim of this descriptive observational study is to explore the activities of OSPs when they are integrated into multidisciplinary care team in RACFs.MethodAn online survey tool was developed to record the activities of OSPs in RACFs using the Qualtrics© software. OSPs were asked questions about their activities in RACFs under categories that included description, time spent, outcomes where applicable and who the pharmacists communicated with to undertake the activity.ResultsSix pharmacists were integrated into 7 RACFs. Overall, they recorded 4252 activities over 12 months. OSPs conducted 1022 (24.0%) clinical medication reviews; 48.8% of medication reviews identified and discussed potentially inappropriate medications with prescribers and 1025 other recommendations were made to prescribers. Overall, the prescriber accepted 51.5% of all recommendations made by OSPs. The most frequently accepted outcome was deprescribing of medications (47.5% for potentially inappropriate medications and 55.5% for other recommendations). OSPs performed facility-level activities including staff education (13.4%), clinical audits (5.8%), and quality improvement activities (9.4%). OSPs spent a large proportion of their time communicating (23.4%) extensively with prescribers, RACF’s healthcare team, and residents.ConclusionOSPs successfully performed a wide range of clinical activities aimed both at improving residents’ medication regimens, and organisational-level quality improvement. The OSP model presents an opportunity for pharmacists to enhance medication management in the residential aged care setting.Trial registrationThe trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN: ACTRN12620000430932) on April 1, 2020